Die sidewall coatings and related methods

ABSTRACT

Various implementations of a method of forming a semiconductor package may include forming a plurality of notches into the first side of a semiconductor substrate; applying a permanent coating material into the plurality of notches; forming a first organic material over the first side of the semiconductor substrate and the plurality of notches; thinning a second side of the semiconductor substrate opposite the first side one of to or into the plurality of notches; and singulating the semiconductor substrate through the permanent coating material into a plurality of semiconductor packages.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of the earlier U.S. UtilityPatent Application to Carney et al. entitled “Die Sidewall Coatings andRelated Methods,” application Ser. No. 16/879,378, filed May 20, 2020,now pending ('378 application); which '378 application is acontinuation-in-part application of the earlier U.S. Utility PatentApplication to Carney et al. entitled “Die Support Structures andRelated Methods,” application Ser. No. 16/861,740, filed Apr. 29, 2020,now pending ('740 application); which '740 application is acontinuation-in-part application of the earlier U.S. Utility PatentApplication to Eiji Kurose entitled “Multi-Faced Molded SemiconductorPackage and Related Methods,” application Ser. No. 16/702,958, filedDec. 4, 2019, now issued as U.S. Pat. No. 11,328,930; which applicationis a divisional application of the earlier U.S. Utility PatentApplication to Eiji Kurose entitled “Multi-Faced Molded SemiconductorPackage and Related Methods,” application Ser. No. 15/679,661, filedAug. 17, 2017, now U.S. Pat. No. 10,529,576, issued Jan. 7, 2020; which'740 application is also a continuation-in-part application of theearlier U.S. Utility Patent Application to Krishnan et al. entitled“Thin Semiconductor Package and Related Methods,” application Ser. No.16/395,822, filed Apr. 26, 2019, now issued as U.S. Pat. No. 10,763,173;which application is a continuation of the earlier U.S. Utility PatentApplication to Krishnan et al. entitled “Thin Semiconductor Package andRelated Methods,” application Ser. No. 15/679,664, filed Aug. 17, 2017,now U.S. Pat. No. 10,319,639, issued Jun. 11, 2019; the disclosures ofeach of which are hereby incorporated entirely herein by reference.

This application is also a continuation-in-part application of theearlier U.S. Utility Patent Application to Carney et al. entitled“Temporary Die Support Structures and Related Methods,” application Ser.No. 16/862,063, filed Apr. 29, 2020, now pending, the disclosure ofwhich is hereby incorporated entirely herein by reference.

This application is also a continuation-in-part application of theearlier U.S. Utility Patent Application to Seddon et al. entitled“Multidie Supports and Related Methods,” application Ser. No.16/862,120, filed Apr. 29, 2020, now pending, the disclosure of which ishereby incorporated entirely herein by reference.

BACKGROUND 1. Technical Field

Aspects of this document relate generally to semiconductor packages,such as wafer scale or chip scale packages. More specificimplementations involve packages including an encapsulating or moldcompound.

2. Background

Semiconductor packages work to facilitate electrical and physicalconnections to an electrical die or electrical component in the package.A protective cover or molding has generally covered portions of thesemiconductor packages to protect the electrical die or electricalcomponent from, among other things, the environment, electrostaticdischarge, and electrical surges.

SUMMARY

In various implementations of a method of forming a semiconductorpackage, the method may include forming a plurality of notches into thefirst side of a semiconductor substrate; applying a permanent coatingmaterial into the plurality of notches; forming a first organic materialover the first side of the semiconductor substrate and the plurality ofnotches; thinning a second side of the semiconductor substrate oppositethe first side one of to or into the plurality of notches; andsingulating the semiconductor substrate through the permanent coatingmaterial into a plurality of semiconductor packages.

Implementations of a method of forming a semiconductor package mayinclude one, all, or any of the following:

The method may include applying one of a second organic material or abackmetal over the second side of the semiconductor substrate.

The perimeter of each of a plurality of semiconductor die included inthe semiconductor substrate each may include a closed shape.

Forming a first organic material over the first side of thesemiconductor substrate further may include forming a permanent diesupport structure, a temporary die support structure, or any combinationthereof including a perimeter including a closed shape.

The method may include forming one of a second permanent die supportstructure or a temporary die support structure coupled to the secondside of the semiconductor substrate.

The one of the permanent die support structure, the temporary diesupport structure, or any combination thereof may include two or morelayers.

In various implementations of a method of forming a semiconductorpackage, the method may include forming a plurality of notches into thefirst side of a semiconductor substrate; applying a permanent coatingmaterial into the plurality of notches; forming a first organic materialover the first side of the semiconductor substrate and the plurality ofnotches; thinning a second side of the semiconductor substrate oppositethe first side toward the plurality of notches; and singulating thesemiconductor substrate through the permanent coating material into aplurality of semiconductor packages.

Various implementations of a method of forming a semiconductor packagemay include one, all, or any of the following:

The method may include applying one of a second organic material or abackmetal over the second side of the semiconductor substrate.

A perimeter of each of a plurality of semiconductor die included in thesemiconductor substrate each may include a closed shape.

Forming a first organic material over the first side of thesemiconductor substrate further may include forming a permanent diesupport structure, a temporary die support structure, or any combinationthereof including a perimeter including a closed shape.

The method may include forming one of a second permanent die supportstructure or a temporary die support structure coupled to the secondside of the semiconductor substrate.

The one of the permanent die support structure, the temporary diesupport structure, or any combination thereof may include two or morelayers.

The method may include forming a second plurality of notches into thesecond side of the semiconductor substrate.

Implementations of a semiconductor device may include a first sideincluding one or more electrical contacts; three or more die side walls;one of a permanent die support structure, a temporary die supportstructure, or any combination thereof coupled to a first side; and anorganic permanent coating material coupled across at least partiallyacross the three or more die side walls.

Implementations of a semiconductor device may include one, all, or anyof the following:

The thickness between the first side and the second side may be between0.1 microns and 125 microns.

The warpage of the first side or the second side may be less than 200microns.

The perimeter of the semiconductor device may be rectangular and a sizeof the first side may be at least 6 mm by 6 mm to 211 mm by 211 mm.

The perimeter of the first side may be a closed shape and the one of thepermanent die support structure, the temporary die support structure, orany combination thereof may include a perimeter including a closedshape.

The device may include one of a second permanent die support structureor a temporary die support structure coupled to the second side.

The one of the permanent die support structure, the temporary diesupport structure, or any combination thereof may include two or morelayers.

The foregoing and other aspects, features, and advantages will beapparent to those artisans of ordinary skill in the art from theDESCRIPTION and DRAWINGS, and from the CLAIMS.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations will hereinafter be described in conjunction with theappended drawings, where like designations denote like elements, and:

FIG. 1 is a cross sectional side view of a semiconductor package;

FIG. 2 is a top view of a semiconductor package;

FIG. 3 is a first process flow illustrating the formation of asemiconductor package;

FIG. 4 is a top view of a semiconductor wafer with a plurality ofnotches cut therein;

FIG. 5 is a top view of a semiconductor wafer with a plurality ofnotches etched therein;

FIG. 6 is a top view of a second implementation of a semiconductor waferwith a plurality of notches etched therein;

FIG. 7 is a top view of a third implementations of a semiconductor waferwith a plurality of notches etched therein;

FIG. 8 is a cross sectional view of a portion of a wafer with moldingapplied thereto;

FIG. 8A is a magnified cross sectional view of the bond between a moldand a sidewall of a notch formed in the die;

FIG. 9 is a second process flow illustrating the formation of asemiconductor package;

FIG. 10 is a third process flow illustrating a portion of the formationof a semiconductor package.

FIG. 11 illustrates a first alternative for forming the notches in thethird process flow.

FIG. 12 illustrates a second alternative for forming the notches in thethird process flow;

FIG. 13 illustrates a third alternative for forming the notches in thethird process flow;

FIG. 14 illustrates a fourth alternative for forming the notches in thethird process flow;

FIG. 15 is a fourth process flow illustrating the formation of asemiconductor package;

FIG. 16 is an illustration of a process flow for forming an ultra-thinsemiconductor package;

FIG. 17 is a cross sectional view of an ultra-thin semiconductor packageformed by the process of FIG. 16;

FIG. 18 is a cross sectional view of an ultra-thin semiconductor packagewith a notch formed therein;

FIG. 19 is an illustration of a process flow for forming an ultra-thinsemiconductor package with a portion of the die exposed;

FIG. 20 is a cross sectional view of an ultra-thin semiconductor packageformed by the process of FIG. 19;

FIG. 21 is an illustration of a process flow for forming an ultra-thinsemiconductor package with a notch formed therein;

FIG. 22 is a cross sectional view of an ultra-thin semiconductor packageformed by the process of FIG. 21;

FIG. 23 is an illustration of a process flow for forming an ultra-thinsemiconductor package with a portion of the die exposed;

FIG. 24 is a cross sectional view of an ultra-thin semiconductor packageformed by the process of FIG. 23;

FIG. 25 is a perspective view of a first implementation of a permanentdie support structure coupled with a thinned semiconductor die (die);

FIG. 26 is a perspective view of a second implementation of a permanentdie support structure coupled with a thinned die;

FIG. 27 is a perspective view of a third implementation of a permanentdie support structure coupled with a thinned die;

FIG. 28 is a perspective view of a fourth implementation of a permanentdie support structure coupled with a thinned die;

FIG. 29 is a perspective view of a fifth implementation of a permanentdie support structure coupled with a thinned die;

FIG. 30 is a perspective view of a sixth implementation of a permanentdie support structure coupled with a thinned die;

FIG. 31 is a perspective view of a seventh implementation of a permanentdie support structure coupled with a thinned die;

FIG. 32 is a perspective view of an eighth implementation of a permanentdie support structure coupled with a thinned die;

FIG. 33 is a perspective view of an ninth implementation of a permanentdie support structure coupled with a thinned die;

FIG. 34 is a perspective view of an tenth implementation of a permanentdie support structure coupled with a thinned die;

FIG. 35 is a perspective view of an eleventh implementation of apermanent die support structure coupled with a thinned die;

FIG. 36 is a perspective view of an twelfth implementation of apermanent die support structure coupled with a thinned die;

FIG. 37 is a perspective view of a thirteenth implementation of apermanent die support structure coupled with a thinned die showing afirst portion of material and a second portion of material;

FIG. 38 is a perspective view of a fourteenth implementation of apermanent die support structure coupled with a thinned die showingfirst, second, third, and fourth portions of material;

FIG. 39 is a perspective view of a fifteenth implementation of apermanent die support structure coupled with a thinned die;

FIG. 40 is a perspective view of a sixteenth implementation of apermanent die support structure coupled with a thinned die;

FIG. 41 is a perspective view of a seventeenth implementation of apermanent die support structure coupled with a thinned die showingfirst, second, third, and fourth portions of material;

FIG. 42 is a perspective view of an eighteenth implementation of apermanent die support structure coupled with a thinned die showingfirst, second, third, and fourth portions of material;

FIG. 43 is a perspective view of a nineteenth implementation of apermanent die support structure coupled with a thinned die showing afirst portion of material and a second portion of material;

FIG. 44 is a perspective view of an twentieth implementation of apermanent die support structure coupled with a thinned die showingfirst, second, and third portions of material;

FIG. 45 is a side cross-sectional view of an implementation of apermanent die support structure coupled with a thinned die;

FIG. 46 is a side cross-sectional view of an implementation of apermanent die support structure coupled with a thinned die;

FIG. 47 is a side view of an implementation of a semiconductor substratewith a molded permanent die support structure coupled following partialsingulation;

FIG. 48 is a top view of a semiconductor substrate with a plurality ofpermanent die support structures coupled over a plurality of die formedtherein;

FIG. 49 is a top view of a die of the plurality of die of FIG. 48showing the permanent die support structure with a varying thicknessacross the die support structure;

FIG. 50 is a side view of the die of FIG. 49 showing the thickness ofthe die and the permanent die support structure;

FIG. 51 is a side view of a semiconductor substrate with a plurality ofsaw streets formed thereon;

FIG. 52 is a side view of a full-thickness (original thickness)semiconductor substrate with a plurality of die with a correspondingplurality of permanent die support structures coupled thereto;

FIG. 53 is a side view of a thinned semiconductor substrate with aplurality of die with a corresponding plurality of permanent die supportstructures coupled thereto applied after thinning;

FIG. 54 is a side view of a thinned semiconductor substrate with aplurality of die with a corresponding plurality of permanent die supportstructures coupled thereto applied after formation of backmetal;

FIG. 55 is a side view of a partially thinned semiconductor substratewith a plurality of die with a corresponding plurality of permanent diesupport structures coupled thereto after a partial grind has beenperformed;

FIG. 56 is a side view of a thinned semiconductor substrate with aplurality of die with a corresponding plurality of permanent die supportstructures coupled thereto after a full grind has been performed butbefore or after a stress relief etching process is carried out;

FIG. 57 is a perspective view of a semiconductor die;

FIG. 58 is a perspective view of an implementation of a temporary diesupport structure (temporary die support) coupled to a largest planarsurface of a semiconductor die;

FIG. 59 a perspective view of another implementation of a second layerof temporary die support being coupled over a first layer;

FIG. 60 is a perspective view of an implementation of a temporary diesupport with two C- or U-shaped portions;

FIG. 61 is a perspective view of an implementation of a temporary diesupport with an X-shape;

FIG. 62 is a perspective view of an implementation of a temporary diesupport with a rod-shape;

FIG. 63 is a perspective view an implementation of a temporary diesupport with a central portion with ribs extending therefrom;

FIG. 64 is a perspective view of an implementation of a temporary diesupport with an elliptical shape;

FIG. 65 is a perspective view of an implementation of a temporary diesupport with a triangular shape;

FIG. 66 is a perspective view of an implementation of a temporary diesupport having two portions;

FIG. 67 is a perspective view of an implementation of a temporary diesupport coupled along a side of a semiconductor die;

FIG. 68 is a perspective view of an implementation of a temporary diesupport with two portions each coupled around a corner of asemiconductor die;

FIG. 69 is a perspective view of an implementation of a temporary diesupport coupled along a side and around a corner of a semiconductor die;

FIG. 70 is a perspective view of an implementation of a temporary diesupport including an elliptical shape;

FIG. 71 is a side view of an implementation of a temporary die supportcoupled over a semiconductor die;

FIG. 72 a side view of an implementation of a conformal temporary diesupport coupled over a semiconductor de;

FIG. 73 is a side view of an implementation of a temporary die supportcoupled partially on a largest planar surface of a semiconductor die;

FIG. 74 is a side view of an implementation of a temporary die supportwith two portions coupled on a largest planar surface of a semiconductordie;

FIG. 75 is a top view of a semiconductor substrate with a plurality ofdie thereon with a corresponding plurality of implementations oftemporary die support structures coupled thereto;

FIG. 76 is a top view of an implementation of a temporary die supportstructure comprising two mirrored curved portions;

FIG. 77 is a side view of an implementation of a temporary die supportstructure with a varying thickness across the structure;

FIG. 78 is a side view of a semiconductor substrate prior to singulationwith a plurality of die thereon following application of a plurality oftemporary die supports thereon;

FIG. 79 is a side view of a semiconductor substrate followingsingulation and following application of a plurality of temporary diesupports thereon;

FIG. 80 is a side view of an implementation of a temporary die supportwhile being peeling from a semiconductor die after exposure to light;

FIG. 81 is a side view of an implementation of a temporary die supportbeing etched from a semiconductor die by a plasma etching process;

FIG. 82 is a view of a liquid bath with an ultrasonic energy sourcetherein along with an implementation of a temporary die support beingpeeled from a semiconductor die under the influence of the ultrasonicenergy;

FIG. 83 is a side view of an implementation of a multi-layer temporarydie support;

FIG. 84 is a perspective view of an implementation of a temporary diesupport with a first layer with a second layer having an opening thereincoupled over the first layer;

FIG. 85 is a side view of an implementation of a temporary die supporthaving a thickness larger than a thickness of a semiconductor die;

FIG. 86 is a side view of an implementation of a semiconductor substratewith a plurality of die streets therein;

FIG. 87 is a top view of two semiconductor die joined through a diestreet/scribe line/saw street;

FIG. 88 is a perspective view of the two semiconductor die of FIG. 87coupled with an implementation of a permanent die support structurecoupled with a lower largest planar surface;

FIG. 89 is a perspective view of the two semiconductor die of FIG. 87coupled with an implementation of a temporary die support structurecoupled with an upper largest planar surface;

FIG. 90 is a perspective view of the two semiconductor die of FIG. 87coupled with an implementation of a die support structure coupled at athickness;

FIG. 91 is a perspective view of an implementation of a die supportstructure that includes a first portion and a second portion coupled toa largest planar surface of two semiconductor die;

FIG. 92 is a perspective view of an implementation of a die supportstructure that is coupled along a largest planar surface of threesemiconductor die;

FIG. 93 is a perspective view of an implementation of an X-shaped diesupport structure coupled to five semiconductor die;

FIG. 94 is a top view of an implementation of an elliptically shaped diesupport structure coupled to four semiconductor die;

FIG. 95 is a top view of an implementation of an irregularly shaped diesupport structure coupled to two semiconductor die of different sizes;

FIG. 96 is a side view of an implementation of a die support structurecoupled to two semiconductor die where the die support is thinner thanthe thickness of the two semiconductor die;

FIG. 97 is a side view of an implementation of a die support structurecoupled to two semiconductor die where the die support is thicker thanthe thickness of the two semiconductor die;

FIG. 98 is a side view of an implementation of a permanent die supportstructure formed of a mold compound coupled to multiple groups of twosemiconductor die during a singulation process;

FIG. 99 is a side view of a plurality of die support structures beingapplied to a plurality of groups of two semiconductor die using a jig;

FIG. 100 is a side view of the plurality of groups of two semiconductordie of FIG. 99 after coupling with a permanent die support structureshowing removal of a temporary die support prior to a singulationprocess;

FIG. 101 is a side view of a thinned semiconductor substrate showing adie support structure coupled over two groups of two semiconductor dieshowing a plurality of die streets;

FIG. 102 is a top view of a semiconductor substrate with a plurality ofdie with a plurality of X-shaped die support structures applied overadjacent groups of 4 die;

FIG. 103 is a top view of two adjacent groups of 4 die with an X-shapeddie support structure applied over each;

FIG. 104 is a top view of a die support comprising multiple curvedportions coupled over two semiconductor die;

FIG. 105 is a side cross sectional view of an implementation of asemiconductor substrate following formation of a plurality of notchestherein;

FIG. 106 is a side cross sectional view of the semiconductor substrateof FIG. 105 with a permanent coating material in the plurality ofnotches;

FIG. 107 is a side cross sectional view of the semiconductor substrateof FIG. 106 following application of a first organic material over thefirst die of the substrate;

FIG. 108 is a side cross sectional view of the semiconductor substrateof FIG. 107 following thinning of the semiconductor substrate; and

FIG. 109 is a side cross sectional view of the semiconductor substrateof FIG. 108 following formation of a second organic material over thesecond side of the substrate;

FIG. 110 is a side cross sectional view of the semiconductor substrateof FIG. 109 following thinning of the first organic material;

FIG. 111 is a side cross sectional view of a plurality of semiconductorpackages following singulation;

FIG. 112 is a side cross sectional view of another semiconductorsubstrate with a plurality of notches formed therein;

FIG. 113 is a side cross sectional view of the semiconductor substrateof FIG. 112 with a permanent coating material applied in the pluralityof notches;

FIG. 114 is a side cross sectional view of the semiconductor substrateof FIG. 113 following application of a first organic material over thefirst side of the semiconductor substrate;

FIG. 115 is a side cross sectional view of the semiconductor substrateof FIG. 114 following thinning of the substrate material;

FIG. 116 is a side cross sectional view of the semiconductor substrateof FIG. 115 following application of a second organic material or abackmetal to the second side of the substrate;

FIG. 117 is a side cross sectional view of the semiconductor substrateof FIG. 116 showing the location of singulation lines through thepermanent coating material;

FIG. 118 is a side cross sectional view of the semiconductor substrateof FIG. 118 following singulation into a plurality of semiconductorpackages;

FIG. 120 is a side cross sectional view of an implementation of asemiconductor package; and

FIG. 121 is a side cross sectional view of an implementation of anothersemiconductor package.

DESCRIPTION

This disclosure, its aspects and implementations, are not limited to thespecific components, assembly procedures or method elements disclosedherein. Many additional components, assembly procedures and/or methodelements known in the art consistent with the intended die supportstructures and related methods will become apparent for use withparticular implementations from this disclosure. Accordingly, forexample, although particular implementations are disclosed, suchimplementations and implementing components may comprise any shape,size, style, type, model, version, measurement, concentration, material,quantity, method element, step, and/or the like as is known in the artfor such die support structures, and implementing components andmethods, consistent with the intended operation and methods.

Referring to FIG. 1, a cross sectional side view of a semiconductorpackage is illustrated. The semiconductor package includes a die 2 whichincludes a first side 4, a second side 6, a third side 8 opposite thesecond side 6, a fourth side, a fifth side opposite the fourth side(both fourth and fifth sides are located into and out of the drawingsurface in this view), and a sixth side 10 opposite the first side 4. Invarious implementations, the second side 6 of the die 2, the third side8 of the die, the fourth side of the die, and/or the fifth side of thedie may include a notch therein.

In various implementations, one or more electrical contacts 12 arecoupled to the first side 4 of the die 2. In various implementations,the electrical contacts are metal and may be, by non-limiting example,copper, silver, gold, nickel, titanium, aluminum, any combination oralloy thereof, or another metal. In still other implementations, theelectrical contacts 12 may not be metallic but may rather be anotherelectrically conductive material.

In various implementations, a first mold compound 14 covers the first,second, third, fourth, and fifth sides of the die. In variousimplementations, the mold compound may be, by non-limiting example, anepoxy mold compound, an acrylic molding compound, or another type ofmaterial capable of physically supporting the die and providingprotection against ingress of contaminants. In various implementations,a laminate resin or second mold compound covers the sixth side 10 of thedie.

The electrical contacts 12 each extend through a corresponding pluralityof openings in the first mold compound 14. In various implementations,the electrical contacts 12 extend beyond the surface of the molding 14,as illustrated in FIG. 1, while in other implementations the electricalcontacts are level or flush with the surface of the molding compound 14.

In various implementations, the sides of the die will have no chips orcracks, particularly on the semiconductor device side of the die. Thisis accomplished through forming the second, third, fourth, and fifthsides of each die using etching techniques rather than a conventionalsawing technique. Such a method is more fully disclosed is associationwith the discussion of FIG. 3 herein.

Further, the first mold compound may be anchored to the second, third,fourth, and fifth sides of the die. In various implementations, theanchor effect is the result of interaction of the mold compound with aplurality of ridges formed along the second, third, fourth, and fifthsides of the die. This anchoring effect is more fully disclose inassociation with the discussion of FIG. 3 herein.

Referring to FIG. 2, a top view of a semiconductor package isillustrated. The molding compound 14 is clearly seen in FIG. 2encompassing a perimeter of each electrical contact 12 (the shaded areasin FIG. 2) so that the entire first side of the die (along with everyother side) is not exposed.

Referring to FIG. 3, a first process flow illustrating the formation ofa semiconductor package is illustrated. In various implementations, themethod for making a semiconductor package includes providing a wafer 16which may include any particular type of substrate material, including,by non-limiting example, silicon, sapphire, ruby, gallium arsenide,glass, or any other semiconductor wafer substrate type. In variousimplementations, a metal layer 18 is formed on a first side 28 of thewafer 16 and may be formed using a sputtering technique. In otherimplementations, the metal layer 18 is formed using other techniques,such as, by non-limiting example, electroplating, electroless plating,chemical vapor deposition, and other methods of depositing a metallayer. In a particular implementation, the metal layer is atitanium/copper seed layer, while in other implementations, the metallayer may include, by non-limiting example, copper, titanium, gold,nickel, aluminum, silver, or any combination or alloy thereof.

In various implementations, a first photoresist layer 20 is formed andpatterned over the metal layer 18. One or more electrical contacts 22may be formed on the metal layer 18 and within the photoresist layer 20.In various implementations this may be done using various electroplatingor electroless plating techniques, though deposition and etchingtechniques could be employed in various implementations. The electricalcontacts 22 may be any type of electrical contact previously disclosedherein (bumps, studs, and so forth). In various implementations, thefirst photoresist layer 20 is removed through an ashing or solventdissolution process and the metal layer 18 may be etched away after theelectrical contacts are formed.

In various implementations, a second photoresist layer 24 is formed andpatterned over the wafer 16. In various implementations, as illustratedin FIG. 3, the second patterned photoresist layer 24 does not cover theelectrical contacts 22. In other implementations, the second photoresistlayer is formed conformally over the electrical contacts along with thewafer. Referring to FIG. 9, a second process flow illustrating theformation of a semiconductor package is illustrated. In this processflow, a second photoresist layer 68 is formed as a conformal layer overthe electrical contacts 70. Aside from this difference, the processdepicted in FIG. 9 includes the same process steps as the processdepicted in FIG. 3.

Referring back to FIG. 3, in various implementations, the methodincludes etching a plurality of notches 26 into the first side 28 of thewafer 16 using the second patterned photoresist layer. In variousimplementations, the width of the notches may be between about 50 andabout 150 microns wide while in other implementations, the width of thenotches may be less than about 50 microns or more than about 150microns. In various implementations, the depth of the plurality ofnotches 26 may extend between about 25 and 200 microns into the waferwhile in other implementations, the depth of the plurality of notches 26may be less than about 25 microns or more than about 200 microns.

In various implementations, the plurality of notches may be formedusing, by non-limiting example, plasma etching, deep-reactive ionetching, or wet chemical etching. In various implementations, a processmarketed under the tradename BOSCH® by Robert Bosch GmbH, StuttgartGermany (the “Bosch process”), may be used to form the plurality ofnotches 26 in the first side 28 of the wafer 16.

Referring now to FIG. 4, a top view of a conventional semiconductorwafer with a plurality of saw cuts surrounding the plurality of die isillustrated. Using a saw to cut notches in a semiconductor waferinvariably results in the production of chips and cracks on the deviceside of the die and in the sidewalls 34 of the notches 30. The presenceof the cracks and chips has the potential to compromise the reliabilityof the semiconductor package if the cracks and chips propagate into thedevice portion of the semiconductor die. Since the saw process involvesthe rubbing of the rotating blade against the die surface, the chippingand cracking can only be managed through saw processing variables (waferfeed speed, blade kerf width, cut depth, multiple saw cuts, bladematerials, etc.) but not eliminated. Furthermore, because the sawprocess relies on passing the wafer underneath the blades, only squareand rectangular sized die are typically produced using conventional sawtechniques.

Referring to FIG. 5, a top view of a semiconductor wafer with aplurality of notches etched therein is illustrated. In contrast to theappearance of the die processed using the conventional sawing methodillustrated in FIG. 4, the plurality of notches 36 in the wafer 38formed using etching techniques have edges and sidewalls 40 that do notexhibit cracks or chips therein. Because of the absence of the cracksand chips, the use of etching techniques to form a plurality of notchesin a semiconductor wafer is likely to improve the reliability of theresulting semiconductor packages.

Furthermore, using etching techniques to form a plurality of notches ina wafer allows for different shapes of perimeters of die to be produced.In various implementations, the second photoresist layer described inrelation to FIG. 3 may be patterned in a way to form a plurality ofnotches that do not form die with rectangular perimeters. For example,referring to FIG. 6, a top view of a second implementation of asemiconductor wafer with a plurality of notches etched therein isillustrated. In various implementations, a plurality of notches 42 maybe formed in a wafer 44. The plurality of notches 42 may form eventualdie 46 with perimeters that are octagons. Referring to FIG. 7, a topview of a third implementations of a semiconductor wafer with aplurality of notches etched therein is illustrated. In variousimplementations, a plurality of notches 48 may be formed in a wafer 50.The plurality of notches 48 may form eventual die 52 with perimetersthat are rounded rectangles. In other implementations, a plurality ofnotches may be formed in a wafer that form eventual die with perimetersthat are any other closed geometrical shape.

Referring back to FIG. 3, in various implementations, the plurality ofnotches 26 formed have two substantially parallel sidewalls that extendsubstantially straight into the first side 28 of the wafer 16. In otherimplementations, two or more stepwise notches are formed in the firstside 28 of the wafer 16. Each stepwise notch may be formed by creating afirst notch in the wafer, and then forming a second narrower notchwithin each first notch.

Referring to FIG. 3, an implementation of a method for forming asemiconductor package includes applying a first mold compound 54 intothe plurality of notches 26 and over the first side of the wafer. Invarious implementations, as illustrated by FIG. 3, the first moldcompound 54 may cover the electrical contacts 22. In otherimplementations, the first mold compound 54 may not completely cover theelectrical contacts 22. The first mold compound may be applied using, bynon-limiting example, a liquid dispensing technique, a transfer moldingtechnique, a printer molding technique, or a compression moldingtechnique. The molding compound may be an epoxy molding compound, anacrylic molding compound, or another type of molding compound disclosedherein.

In various implementations, the first mold compound 54 may be anchoredto a plurality of sidewalls 56 of a plurality of notches 26. Referringnow to FIG. 8, a cross sectional view of a portion of a wafer withmolding applied thereto is illustrated. Referring now to FIG. 8A, amagnified cross sectional view of the bond between a mold and a sidewallof a notch formed in the die is illustrated. In various implementations,a plurality of ridges 58 may be formed in a sidewall 56 of each notchwithin the plurality of notches. In a particular implementation, theheight of each ridge extending from the sidewall is substantially 0.2microns tall with a pitch of substantially one micron. Thus, inimplementations where the notch is 150 microns deep, there may besubstantially 150 microns on each sidewall of the notch. In otherimplementations, the notches may be taller or shorter than 0.2 micronsand may have a pitch more or less than one micron. The ridges may anchorthe first mold compound 54 to the sidewalls 56 of the plurality ofnotches. In various implementations where the plurality of notches areetched using the Bosch process, the etching process may form ridges inthe plurality of notches while etching the plurality of notches via thedeposition/etching cycles of the deep reactive ion etch, thus increasingthe adhesion between the first mold compound and the sidewall of eachnotch.

Referring back to FIG. 3, in various implementations where the firstmold compound 54 covers the electrical contacts 22, the electricalcontacts 22 may be exposed by grinding the first mold compound. Invarious implementations, a second side 60 of the wafer 16 may be groundto the plurality of notches 26 formed in the first side 28 of the wafer16. In this way the various die of the semiconductor wafer aresingulated from each other. In various implementations, the second side60 of the wafer 16 may be ground using, by non-limiting example, amechanical polishing technique, a chemical etching technique, acombination of a mechanical polishing and chemical etching technique, orany other grinding technique.

In various implementations, a second mold compound 62 or a laminateresin may be applied to the second side 60 of the wafer 16. Inimplementations where a second mold compound is applied, the moldcompound may be any type of mold compound disclosed herein and may beapplied using any technique disclosed herein.

In various implementations, as illustrated in the process flow depictedin FIG. 3, the first mold compound 54 is ground to expose the electricalcontacts 22 before the second side 60 of the wafer 16 is ground and thesecond mold compound is applied. In other implementations, the firstmold compound 54 may be ground to expose the electrical contacts 22after the second side 60 of the wafer 16 is ground and the second moldcompound is applied.

The method for making a semiconductor package includes singulating thewafer 16 into a plurality of semiconductor packages 64. The wafer 16 maybe singulated by cutting or etching through the wafer where theplurality of notches 26 were originally formed. The wafer may besingulated by using, by non-limiting example, a saw, a laser, awaterjet, plasma etching, deep reactive-ion etching, or chemicaletching. In various implementations, the Bosch process may be used tosingulate the wafer 16. The method used to singulate the wafer mayinclude singulating the wafer using thinner cuts or etches than wereused to form the plurality of notches 26. In this manner, the first moldcompound will cover the sides of each singulated die 66 within eachsemiconductor package 64. Specifically, in particular implementationsthe saw width used to singulate each semiconductor package may bebetween 20 and 40 microns thick. The semiconductor die within thesemiconductor package may be covered by either a mold compound or alaminate resin on all six sides of the semiconductor die.

In various implementations, the first side of the die within eachsemiconductor package may include a perimeter that is, by non-limitingexample, a rectangle, an octagon, a rectangle with rounded edges, or anyother closed geometric shape.

Referring now to FIG. 10, a third process flow illustrating a portion ofthe formation of a semiconductor package is illustrated. In variousimplementations the method for forming a semiconductor package includesproviding a wafer 72, which may be any type of wafer substrate disclosedherein. In various implementations, one or more metal pads 74 may becoupled to a first side 76 of the wafer 72. The metal pad may include,by non-limiting example, aluminum, copper, nickel silver, gold,titanium, or any combination or alloy thereof.

In various implementations, a first passivation layer 78 may be coupledto a portion of the first side 76 of the wafer 72. The first passivationlayer 78 may be a silicon dioxide passivation layer in variousimplementations, though it could be any of a wide variety of other typesof layers, including, by non-limiting example, silicon nitride,polyimide, or another polymer or deposited material. In variousimplementations, a second passivation layer 80 may be coupled to aportion of the first side 76 of the wafer 72. The second passivationlayer 80 may be a silicon nitride passivation layer. The secondpassivation layer may include the same material or a different materialfrom the first passivation layer.

In various implementations, a third layer 82 may be coupled to a portionof the first side 76 of the wafer 72. The third layer may be either apolyimide, a polybenzoxazole, a phenol resin, or a combination of apolyimide, a polybenzoxazole, and a phenol resin. In variousimplementations, a metal seed layer 84 may be formed over the thirdlayer and over the first side 76 of the wafer 72. The metal seed layer84 may be any type of metal layer disclosed herein. In variousimplementations, the metal seed layer 84 may directly contact portionsof the first side 76 of the wafer 72. In various implementations, themethod includes forming and patterning a first photoresist layer 86 overthe metal seed layer 84.

In various implementations, the method includes forming electricalcontacts 88 coupled to the metal seed layer 84 and within the firstphotoresist layer 86. The electrical contacts 88 may be any type ofelectrical contact disclosed herein. In various implementations, theelectrical contacts 88 may include a first layer 90 and a second layer92. In various implementations, the first layer 90 may include copperand the second layer 92 may include tin, silver, or a combination of tinand silver. In various implementations, the method of forming asemiconductor package includes removing the first photoresist layer 86and etching the portions of the metal seed layer 84 away that are notcovered by the electrical contacts, after the electrical contacts areformed.

In various implementations, the method of forming a semiconductorpackage includes forming and patterning a second photoresist layer 94over the first side 76 of the wafer 72. In various implementations, thesecond photoresist layer covers the electrical contacts 88, while inother implementations, the second photoresist layer 94 does not coverthe electrical contacts 88. The second photoresist layer 94 may be usedto etch a plurality of notches 96 into the wafer 72. The method includesremoving the second photoresist layer 94 after the plurality of notchesare etched into the wafer.

A first mold compound may be applied into the plurality of notches andover the first side 76 of the wafer 72 in the same manner the first moldcompound in FIG. 3 is applied. The remainder of the method for forming asemiconductor package as depicted in FIG. 10 may include exposing theelectrical contacts through grinding, grinding the backside of the waferto the plurality of notches, applying a second mold compound or laminateresin to a backside of the wafer, and singulating the wafer into aplurality of semiconductor packages. These portions of forming asemiconductor package may be the same as or similar to respectiveportions for forming a semiconductor package illustrated by FIG. 3 andpreviously disclosed herein.

In various implementations, the semiconductor package produced by themethod depicted in FIG. 10 may include one or more metal pads, one ormore passivation layers, a polyimide, a phenol resin, a polybenzoxazole,and any combination thereof, between the semiconductor die and the firstmold compound.

Referring to FIGS. 11-14, alternative methods for forming a plurality ofnotches in the process illustrated by FIG. 10 is illustrated. Referringto FIG. 11, a method of forming a plurality of notches using a patternedphotoresist layer and one of a polyimide, polybenzoxazole, and a phenolresin in combination with an etching process is illustrated. In variousimplementations, a patterned photoresist layer 98 may be over a mask 100including either a patterned polyimide layer, a patternedpolybenzoxazole layer, or a patterned phenol resin layer. The mask 100may be over a wafer 102. A notch 104 may be formed in the wafer 102using the patterned photoresist layer and the mask using any etchingprocess disclosed herein.

Referring to FIG. 12, a method of forming a plurality of notches usingone of a polyimide, polybenzoxazole, and a phenol resin in combinationwith any etching process disclosed herein is illustrated. The method maybe the same as the method depicted by FIG. 11, with the difference beingthat the method depicted by FIG. 12 does not include a patternedphotoresist layer used to form a notch 106 into a wafer 108.

Referring to FIG. 13, a method of forming a plurality of notches using apatterned photoresist layer and passivation mask is illustrated. Invarious implementations, a patterned photoresist layer 110 may be over apassivation mask 112. The passivation mask 112 may include anypassivation layer disclosed herein. The passivation mask 112 may be overa wafer 114. A notch 116 may be formed in the wafer 114 using thepatterned photoresist layer 110 and the passivation mask 112 and anyetching process disclosed herein.

Referring to FIG. 14, a method of forming a plurality of notches using apassivation mask in combination with any of the etching method disclosedherein is illustrated. The method may be the same as the method depictedby FIG. 13, with the difference being that the method depicted by FIG.14 does not include a patterned photoresist layer used to form a notch116 into a wafer 118.

Referring to FIG. 15, a fourth process flow illustrating the formationof a semiconductor package is illustrated. The method for forming asemiconductor package illustrated in FIG. 15 includes providing a wafer120. In various implementations, an interlayer 122 may be coupled to afirst side 124 of the wafer 120. In various implementations, apassivation layer 128 may be coupled to the wafer 120. The passivationlayer may be any type of passivation layer disclosed herein.

In various implementations, one or more electrical contacts 126 may becoupled to the wafer 120. In various implementations, the electricalcontacts include a bump 130. The electrical contacts may include a firstmetal layer 132 coupled to the bump 130. The first metal layer mayinclude any metal disclosed herein. In a particular implementation, thefirst metal layer includes nickel and gold. The electrical contacts 128may include a second metal layer 134 coupled to the first metal layer132. The second metal layer 134 may include any metal disclosed herein.In a particular implementation, the second metal layer 134 includesaluminum. In various implementations, a solder resist layer 136 may becoupled over the wafer 120. In other implementations, no solder resistlayer is included.

In various implementations, the passivation layer 128 may be patternedand may directly contact portions of the wafer 120. In suchimplementations, the patterned passivation layer, or mask, may be usedto etch a plurality of notches 138 into the first side 124 of the wafer120 using any etching process disclosed herein. The plurality of notchesmay be etched using any method disclosed herein, and may be any type ofnotch previously disclosed herein.

In various implementations, a first mold compound 140 is applied intothe plurality of notches 138 and over the first wafer 120. The firstmold compound 140 may be any mold compound disclosed herein and may beapplied using any technique disclosed herein. In variousimplementations, the first mold compound 140 does not entirely cover theelectrical contacts 126, as is illustrated by FIG. 15. In otherimplementations, the first mold compound does entirely cover theelectrical contacts 126. In implementations where the first moldcompound 140 does entirely cover the electrical contacts 126, the firstmold compound may be ground to expose the electrical contacts 126.

In various implementations, a second side 142 opposite the first side124 of the wafer 120 may be ground using any grinding method disclosedherein to the plurality of notches. A second mold compound 144 orlaminate resin may then be applied to the second side 142 of the wafer120.

The wafer 120 may then be singulated into a plurality of semiconductorpackages 146. The wafer may be singulated using any technique disclosedherein. The semiconductor die 148 with the semiconductor package 146 mayhave all six sides covered by a mold compound. In other implementations,the sixth side of the die 150 may be covered by a laminate resin.

In various implementations, the semiconductor package formed by themethod illustrated in FIG. 15 may include either a solder resist layer,a passivation layer, an interlayer, or a combination of a solder resistlayer, a passivation layer, and an interlayer coupled to the first sideof the wafer and covered by the first mold compound.

Referring to FIG. 16, a process flow for forming an ultra-thinsemiconductor package is illustrated. As used herein, an “ultra-thin”semiconductor package is designed to handle a device die of about 25microns in thickness or thinner. The process flow illustrates crosssectional side views of the wafer and die. In various implementations, amethod for forming an ultra-thin semiconductor package includesproviding a wafer 152 with a first side 154 and a second side 156. Thewafer 152 may include a substrate material which may be, by non-limitingexample, silicon, gallium nitride, silicon carbide, or another wafersubstrate material. The first side of the wafer 154 includes or iscoupled to a plurality of electrical contacts 158. The electricalcontacts 158 may be metallic or made of another material that iselectrically conductive.

In various implementations, the method for forming the ultra-thinsemiconductor package includes forming a plurality of notches 160 in thefirst side 154 of the wafer 152. While not shown in FIG. 16, it isunderstood that the plurality of notches intersect one another in asubstantially perpendicular direction across the first side 154 of thewafer 152. In various implementations, the notches formed may extendabout 25 or more microns deep into the wafer. In other implementations,the notches 160 only extend between about 10 and about 25 microns deepin the wafer 152. In still other implementations, the notches 160 extendless than about 10 microns deep in the wafer 152. The plurality ofnotches may be formed using, by non-limiting example, a saw, a laser, awaterjet, plasma etching, or chemical etching. In variousimplementations, a chemical etching process marketed under the tradenameBOSCH® (the “Bosch process”) by Robert Bosch GmbH, Stuttgart Germany,may be used to form the notches 160 in the first side 154 of the wafer152.

In various implementations, the notches 160 formed have twosubstantially parallel sidewalls that extend substantially straight intothe first side 154 of the wafer 152. In other implementations, aplurality of stepwise notches are formed in the first side 154 of thewafer 152. Each stepwise notch may be formed by forming a first notch inthe wafer having a first width, and then forming a second notch with asecond width within each first notch where the first width is wider thanthe second width.

The method for forming the ultra-thin semiconductor package includescoating the first side 154 of the wafer 152 and the interiors of theplurality of notches 160 with a molding compound 162. The moldingcompound may also cover the electrical contacts 158 in various methodimplementations. The molding compound 162 may be applied using, bynon-limiting example, a liquid dispensing technique, a transfer moldingtechnique, or a compression molding technique.

The molding compound may be an epoxy molding compound, an acrylicmolding compound, or any other molding compound capable of hardening andproviding physical support and/or humidity protection to a semiconductordevice. In various implementations, the molding compound 162 may becured under a temperature between about 100-200 degrees Celsius andwhile a pressure of substantially 5 psi is applied to the second side156 of the wafer. In other implementations, the molding may be curedwith different temperatures and different pressures. In implementationswith an epoxy molding compound, after the molding compound 162 isapplied, it may be heat treated to enhance the epoxy cross linking.

In various implementations, the method for forming an ultra-thinsemiconductor package includes grinding the second side 156 of the wafer152 to a desired thickness. In various implementations the second side156 of the wafer 152 may be ground away to an extent that the pluralityof notches 160 filled with molding compound 162 extends completelythrough the wafer. In various implementations, more than this may beground away, thus decreasing the depth of the notches 160. In this waythe semiconductor devices in the wafer are separated from each other,but still held together through the molding compound. Because themolding compounds now supports the semiconductor devices, the devicescan be ground very thin. In various implementations, the second side 156of the wafer 152 may be ground using, by non-limiting example, amechanical polishing technique, a chemical etching technique, acombination of a mechanical polishing and chemical etching technique, orany other grinding technique. In various implementations, the wafer isground to a thickness between about 10 and about 25 microns. In otherimplementations, the wafer is ground to a thickness less than about 10microns. In still other implementations, the wafer may be ground to athickness more than about 25 microns.

In various implementations, the method for forming an ultra-thinsemiconductor package includes forming a back metal 164 on the secondside 156 of the wafer 152. The back metal may include a single metallayer or multiple metal layers. In various implementations, the backmetal may include, by non-limiting example, gold, titanium, nickel,silver, copper, or any combination and/or alloy thereof. Because thewafer 152 is thinned and the back metal 164 is applied to the thinnedwafer while the entirety of the molding compound 162 is coupled to thefront side 154 of the wafer 152 and the interior of the notches 160, itmay be possible to reduce or eliminate warpage of the wafer. Further,wafer handling issues are reduced when thinning the wafer and applyingthe back metal 164 because the entirety of the molding compound 162 isstill coupled to the wafer 152. Furthermore, curling and warpage of theextremely thin semiconductor die now coated with back metal aresignificantly reduced due to the support provided by the moldingcompound.

In various implementations, the method for forming an ultra-thinsemiconductor package includes exposing the plurality of electricalcontacts 158 covered by the molding compound 162 by grinding a firstside 166 of the molding compound 162. The first side 166 of the moldingcompound 162 may be ground using, by non-limiting example, a mechanicalpolishing technique, a chemical etching technique, a combination of amechanical polishing and chemical etching technique, or other grindingtechnique.

In various implementations, the method for forming an ultra-thinsemiconductor package includes singulating the wafer 152 into singledie. The wafer may be singulated by cutting or etching through the waferwhere the plurality of notches 160 were originally formed. The wafer maybe singulated by using, by non-limiting example, a saw, a laser, awaterjet, plasma etching, or chemical etching. In variousimplementations, the Bosch process previously mentioned may be used tosingulate the wafer 152. The method used to the singulate the wafer mayinclude singulating the wafer using thinner cuts or etches than wereused to form the plurality of notches 160. In this manner, the moldingcompound 162 will cover the sides of each singulated die 168.

Referring to FIG. 17, a cross sectional view of an ultra-thinsemiconductor package formed by the process of FIG. 16 is illustrated.In various implementations, the ultra-thin semiconductor package 170 maybe a power semiconductor package. Specifically, the ultra-thinsemiconductor package may be a MOSFET. In other implementations, theultra-thin semiconductor package 170 is not used for a powersemiconductor device, but may be used for other semiconductor devicetypes. In various implementations, the ultra-thin semiconductor packagehas a plurality of electrical contacts 186 coupled to the first side 174of the die and exposed through a first molding compound 184. In variousimplementations, the die 172 of the semiconductor package 170 may bebetween about 10-25 microns thick. In other implementations, the die 172is less than about 10 microns thick. In still other implementations, thedie 172 may be more than about 25 microns thick. The ultra-thin natureof the power semiconductor package may improve the R_(DS(ON)) of thepackage and/or semiconductor device/die.

In various implementations, the ultra-thin semiconductor package 170 iscovered by the first molding compound 184 on a first side 174, a secondside 176, a third side 178, a fourth side, and a fifth side of the die172. A metal layer 180 may be coupled to a sixth side 182 of the die. Invarious implementations, more than one metal layer may be coupled to thesixth side 182 of the die. The metal may include, by non-limitingexample, gold, titanium, nickel, silver, copper, or any combination oralloy thereof.

Referring now to FIG. 18, a cross sectional view of an ultra-thinsemiconductor package with a notch formed therein is illustrated. Thepackage illustrated in FIG. 18 may be the same or similar to the packageillustrated in FIG. 17, with the exception that the package illustratedin FIG. 18 includes a notch 188 around a perimeter of the first side 192of the die 190. The notch 188 may result from forming a stepwise notchin a wafer as described above in relation to FIG. 16. In variousimplementations, the stepwise notch may not extend around the entireperimeter of the die, but may be formed just along two opposing edges ofthe first side 192 of the die 190.

Referring to FIG. 19, a process flow for another implementation of amethod of forming an ultra-thin semiconductor package with a portion ofthe die exposed is illustrated. The method implementation illustrated inFIG. 19 is the same as the process illustrated by FIG. 16, with theexception that the second side 194 of the wafer 196 is not groundthrough to the plurality of notches 198. Because of this, a portion 200of the wafer 196 exists between the plurality of notches 198 and theback metal 202. In various implementations, about 90-95% of the backportion 194 of the wafer 196, or the portion of the wafer that extendsfrom the second side 194 of the wafer to the plurality of notches 198,is removed through grinding. In other implementations, more or less thanthis may be removed through grinding. The other process steps in themethod implementation (molding, grinding, and singulation, etc.) arecarried out similarly to the method implementation illustrated in FIG.16 and described herein.

Referring to FIG. 20, a cross sectional view of an ultra-thinsemiconductor package formed by the process of FIG. 19 is illustrated.The semiconductor package of FIG. 20 may be the same as thesemiconductor package of FIG. 17, with the exception that a portion ofthe die 208 is present between the molding compound and the back metalalong the sides of the die. Thus, in the implementation illustrated byFIG. 20, a portion of the die 208 is exposed on the various opposingsides of the die.

Referring to FIG. 21, a process flow for another implementation offorming an ultra-thin semiconductor package with a notch formed thereinis illustrated. The process flow illustrates cross sectional side viewsof the wafer and die. In various implementations, the method includesproviding a wafer. The wafer has a first side 212 and a second side 214.The wafer may be, by non-limiting example, silicon, gallium nitride,silicon carbide, or other wafer material like those disclosed herein.The first side 212 of the wafer includes or is coupled to a plurality ofelectrical contacts 216. The electrical contacts 216 may be metallic ormade of any other electrically conductive material disclosed herein.

In various implementations, the method includes forming a plurality ofnotches 218 in the first side 212 of the wafer. While not illustrated inFIG. 21, it is understood that the plurality of notches intersect oneanother in a substantially perpendicular direction. The notches 218formed may be any depth previously disclosed herein, any shapepreviously disclosed herein (including stepwise), and formed using anymethod previously disclosed herein.

The method for forming the ultra-thin semiconductor package of FIG. 21includes coating the first side 212 of the wafer and the interiors ofthe plurality of notches 218 with a molding compound 220. The moldingcompound may also cover the electrical contacts 216. The moldingcompound 220 may be applied using any method previously disclosedherein, and may be any type of molding compound previously disclosedherein. In various implementations, the molding compound may be cured orheat treated as described above in relation to FIG. 16.

In various implementations, the method for forming an ultra-thinsemiconductor package includes grinding the second side 214 of the waferto a desired thickness. The second side of the wafer may be ground usingany grinding method disclosed herein, and may be ground to any thicknessdescribed herein. In various implementations the second side 214 of thewafer may be ground away to an extent that the plurality of notches 218filled with molding compound 220 extend completely through the wafer. Invarious implementations, more of the wafer material (and,correspondingly some of the molding compound) may be ground away, thusdecreasing the depth of the notches 220.

In various implementations, the method for forming an ultra-thinsemiconductor package includes forming a back metal 222 on the secondside 214 of the wafer. The back metal may include a single metal layeror multiple metal layers. In various implementations, the back metal mayinclude, by non-limiting example, gold, titanium, nickel, silver,copper, or any combination thereof.

The method of forming the ultra-thin semiconductor package asillustrated in FIG. 21 includes forming at least one groove 224 throughthe back metal 222. In various implementations, the at least one grooveis aligned with a notch from the plurality of notches 218. In variousimplementations, there is a groove formed for every notch. In variousimplementations, the groove is wider than the notch, while in otherimplementations, the groove is as wide as, or less wide than, thecorresponding notch. As illustrated in FIG. 21, the groove 224 mayextend into the second side 214 of the wafer. In other implementations,the groove 224 may only extend through the thickness of the back metal222.

Because the wafer is thinned and the back metal 222 is applied to thethinned wafer while the entirety of the first molding compound 220 iscoupled to the front side 212 of the wafer and the interior of thenotches 218, it reduces warpage of the wafer. Further, wafer handlingissues are reduced when thinning the wafer, applying the back metal 222,and forming the at least one groove 224 through the back metal becausethe entirety of the molding compound 220 is still coupled to the waferas previously discussed.

The method implementation illustrated in FIG. 21 includes coating thesecond side 214 of the wafer and the back metal layer 222 with a secondmolding compound 226. In this manner, as illustrated by FIG. 21, thefirst molding compound and the second molding compound may completelyencapsulate the electrical contacts 216, the wafer, and the back metal222. The second molding compound may be any type disclosed herein andmay be applied and cured using any method described herein. In variousimplementations, the second molding compound may be chemically the sameas the first molding compound, but it may be chemically different inother implementations. The method implementation illustrated in FIG. 21includes grinding the second molding compound to a desired thickness. Invarious implementations, the second molding compound is ground to exposethe back metal 222. The second molding compound may be ground using anygrinding method disclosed herein.

In various implementations, the method for forming an ultra-thinsemiconductor package includes exposing the plurality of electricalcontacts 216 covered by the molding compound 220 by grinding a firstside 228 of the molding compound 220. The first side 228 of the moldingcompound 220 may be ground using any method disclosed herein.

In various implementations, the method for forming an ultra-thinsemiconductor package also includes singulating the wafer, first moldingcompound 220, and second molding compound 226 into single die packages(or multi-die packages as desired). The wafer may be singulated bycutting or etching through the wafer where the plurality of notches 218were originally formed. The wafer may be singulated by using, bynon-limiting example, a saw, a laser, a waterjet, plasma etching, orchemical etching. In various implementations, the Bosch process may beused to singulate the wafer, first molding compound 220, and secondmolding compound 226 into individual packages. The method used to thesingulate the wafer may include singulating the wafer using thinner cutsor etches than were used to form the plurality of notches 218. In thismanner the first molding compound 220 and second molding compound 226cover all the sides of each singulated die 230 leaving the electricalcontacts exposed.

Referring to FIG. 22, a cross sectional view of an ultra-thinsemiconductor package formed by the process of FIG. 21 is illustrated.In various implementations, the ultra-thin semiconductor package 232 mayinclude a power semiconductor device. Specifically, the ultra-thinsemiconductor package may include a MOSFET. In other implementations,the ultra-thin semiconductor package 232 may not include a powersemiconductor device.

In various implementations, the ultra-thin semiconductor package 232 hasa plurality of electrical contacts 234 coupled to the first side 236 ofthe die and exposed through a first molding compound 90.

In various implementations, the die 238 of the semiconductor package 232may be between about 10-25 microns thick. In other implementations, thedie 238 is less than about 10 microns thick. In still otherimplementations, the die 238 may be more than about 25 microns thick. Aspreviously discussed, the ultra-thin nature of the power semiconductorpackage may improve the R_(DS(ON)) of the package.

In various implementations, the ultra-thin semiconductor package 232 iscovered by the first molding compound 240 on a first side 236 and by thefirst molding compound 240 and the second molding compound 298 on asecond side 244, a third side 246, a fourth side, and a fifth side ofthe die 238. In various implementations, the top 252 of the notch 254may be considered part of the sixth side 248 of the die. In this sense,the die may be covered by the second molding compound 298 on the sixthside of the die. A metal layer 250 may be coupled to the sixth side 248of the die. In various implementations, more than one metal layer may becoupled to the sixth side 248 of the die. The metal may include, bynon-limiting example, gold, titanium, nickel, silver, copper, or anycombination or alloy thereof. In various implementations, the notch 254may extend around a perimeter of the die. In various implementations, amolding compound may cover the sides 256 of the metal layer 250.

Referring now to FIG. 23, another implementation of process flow for amethod implementation for forming an ultra-thin semiconductor devicewith a portion of the die exposed is illustrated. The process flowillustrates cross sectional side views of the wafer and die. In variousimplementations, the method includes providing a wafer 258. The wafer258 has a first side 260 and a second side 262. The wafer 258 may be, bynon-limiting example, silicon, gallium nitride, silicon carbide, orother wafer substrate material disclosed herein. The first side 260 ofthe wafer 258 includes or is coupled to a plurality of electricalcontacts 264. The electrical contacts 264 may be metallic or any otherelectrically conductive material disclosed herein.

In various implementations, the method for forming the ultra-thinsemiconductor package includes forming a plurality of notches 266 in thesecond side 262 of the wafer 258. While not shown in FIG. 23, it isunderstood that the plurality of notches intersect one another in asubstantially perpendicular direction. The notches 266 formed may be anydepth previously disclosed herein, any shape previously disclosedherein, and formed using any method previously disclosed herein.

The method for forming the ultra-thin semiconductor package of FIG. 23includes coating the first side 260 of the wafer 258 with a firstmolding compound 268. The first molding compound 268 may also cover theelectrical contacts 264. The first molding compound 268 may be appliedusing any method previously disclosed herein, and may be any typepreviously disclosed herein. In various implementations, the firstmolding compound 268 may be cured or heat treated as described above inrelation to FIG. 16.

In various implementations, the method for forming an ultra-thinsemiconductor package may include grinding the second side 262 of thewafer 258 to a desired thickness. The second side of the wafer may beground using any grinding method disclosed herein, and may be ground toany thickness described herein that still allows the notches to exist inthe material of the wafer itself. In other implementations, the secondside of the wafer is not ground.

The method of forming the ultra-thin semiconductor package asillustrated in FIG. 23 includes coating the second side 262 of the wafer258 and the interiors of the plurality of notches 266 with a secondmolding compound 274. The second molding compound may be any typedisclosed herein and may be applied and cured using any method describedherein.

The method of forming the ultra-thin semiconductor package asillustrated in FIG. 23 includes grinding the second molding compound 274to a desired thickness. In various implementations, the second moldingcompound is ground to expose the second side of the wafer 262. Invarious implementations, a portion of the wafer may be ground away withthe second molding compound 274. At least a portion of the plurality ofnotches 266 remains after grinding the second molding compound 274. Thesecond molding compound 274 may be ground using any grinding methoddisclosed herein.

In various implementations, the method for forming an ultra-thinsemiconductor package includes forming a back metal 270 on the secondside 262 of the wafer 258 and over the plurality of notches 266. Theback metal may include a single metal layer or multiple metal layers. Invarious implementations, the back metal may include, by non-limitingexample, gold, titanium, nickel, silver, copper, or any combination oralloy thereof.

Because the wafer 258 may be thinned and the back metal 270 is appliedto the thinned wafer while the entirety of the first molding compound268 is coupled to the front side 260 of the wafer 258, it reduceswarpage of the wafer. Further, as discussed in this document, waferhandling issues are reduced when thinning the wafer and applying theback metal 270 because the entirety of the molding compound 268 is stillcoupled to the wafer 258.

In various implementations, the method for forming an ultra-thinsemiconductor package includes exposing the plurality of electricalcontacts 264 covered by the first molding compound 268 by grinding afirst side 272 of the first molding compound. The first side 272 of thefirst molding compound 268 may be ground using any method disclosedherein.

In various implementations, the method for forming an ultra-thinsemiconductor package includes singulating the wafer 258, first moldingcompound 268, and second molding compound 274 into single die 276. Thewafer may be singulated by cutting or etching through the wafer wherethe plurality of notches 266 were originally formed. The wafer may besingulated by using, by non-limiting example, a saw, a laser, awaterjet, plasma etching, or chemical etching. In variousimplementations, the Bosch process may be used to singulate the wafer258, first molding compound 268, and second molding compound 274 intoindividual die.

Referring to FIG. 24, a cross sectional view of an ultra-thinsemiconductor package formed by the process of FIG. 23 is illustrated.In various implementations, the ultra-thin semiconductor package 278 mayinclude a power semiconductor device. Specifically, the ultra-thinsemiconductor package may include a MOSFET. In other implementations,the ultra-thin semiconductor package 278 may not include a powersemiconductor device. In various implementations, the ultra-thinsemiconductor package 278 has a plurality of electrical contacts 280coupled to the first side 282 of the die 284. In variousimplementations, the die 284 of the semiconductor package 278 may bebetween about 10-25 microns thick. In other implementations, the die 284is less than about 10 microns thick. In still other implementations, thedie 284 may be more than about 25 microns thick. As previouslydiscussed, the ultra-thin nature of the power semiconductor device mayimprove the R_(DS(ON)) of the device.

In various implementations, the ultra-thin semiconductor package 278includes a molding 286 on a portion of a first side 282, a portion of asecond side 288, a portion of a third side 290, a portion of a fourthside, and a portion of a fifth side of the die 284. A metal layer 294may be coupled to the sixth side 292 of the die. In variousimplementations, more than one metal layer may be coupled to the sixthside 292 of the die. The metal may include, by non-limiting example,gold, titanium, nickel, silver, copper, or any combination or alloythereof. In various implementations, a notch 296 cut out of the sixthside 292 of the die may extend around a perimeter of the die 284.

Referring to FIG. 25, a first implementation of a semiconductor device300 is illustrated. As illustrated, the device 300 includes a permanentdie support structure (die support structure) 302 coupled with a thinnedsemiconductor die 304. The semiconductor die 304 may include one or moresemiconductor devices formed therein and/or thereon including, bynon-limiting example, integrated bipolar junction transistors (IGBTs),metal oxide semiconductor field effect transistors (MOSFETs), diodes,power semiconductor devices, any semiconductor device disclosed in thisdocument, any combination thereof, or any other active or passivesemiconductor device or component, alone or in combination. Asillustrated, the semiconductor die 304 has a first largest planarsurface 306 that, in this implementation, opposes a second largestplanar surface 308. Between the first largest planar surface 306 and thesecond largest planar surface 308 is thickness 310 of the semiconductordie 304. The die in the implementation illustrated in FIG. 25 alsoincludes four sides that extend across the thickness 310, two of which,312 and 314, are visible in FIG. 25. The semiconductor die 304 has aperimeter 316 that extends around at least one of the first largestplanar surface 306 or the second largest planar surface 308. In theimplementation illustrated, the semiconductor die 304 is rectangular,and so the perimeter 316 forms a rectangular shape. In variousimplementations of semiconductor die disclosed herein, however, theperimeter may be, by non-limiting example, elliptical, triangular,circular, rhomboidal, polygonal, hexagonal, or any other closed shape.

In various implementations disclosed herein, the thickness 310 of thethinned semiconductor die may be between about 0.1 microns and about 125microns. In other implementations, the thickness may be between about0.1 microns and about 100 microns. In other implementations, thethickness may be between about 0.1 microns and about 75 microns. Inother implementations, the thickness may be between about 0.1 micronsand about 50 microns. In other implementations, the thickness may bebetween about 0.1 microns and about 25 microns. In otherimplementations, the thickness may be between about 0.1 microns andabout 10 microns. In other implementations, thickness may be between 0.1microns and about 5 microns. In other implementations, the thickness maybe less than 5 microns.

The various semiconductor die disclosed herein may include various diesizes. Die size generally refers to measured principal dimensions of theperimeter of the die. For example, for a rectangular die that is asquare, the die size can be represented by referring to a height andwidth of the perimeter. In various implementations, the die size of thesemiconductor die may be at least about 4 mm by about 4 mm where theperimeter of the die is rectangular. In other implementations, the diesize may be smaller. In other implementations, the die size of thesemiconductor die may be about 211 mm by about 211 mm or smaller. Fordie with a perimeter that is not rectangular, the surface area of thelargest planar surface of die may be used as a representation of the diesize.

One of the effects of thinning the semiconductor die is that as thethickness decreases, the largest planar surfaces of the die may tend towarp or bend in one or more directions as the thinned material of thedie permits movement of the material under various forces. Similarwarping or bending effects may be observed where the die size becomesmuch larger than the thickness of the die for large die above about 6 mmby about 6 mm or 36 mm² in surface area. These forces include tensileforces applied by stressed films, stress created through backgrinding,forces applied by backmetal formed onto a largest planar surface of thedie, and/or forces induced by the structure of the one or more devicesformed on and/or in the semiconductor die. This warping or bending ofthe thinned semiconductor die can prevent successful processing of thedie through the remaining operations needed to form a semiconductorpackage around the die to allow it to ultimately function as, bynon-limiting example, a desired electronic component, processor, powersemiconductor device, switch, or other active or passive electricalcomponent. Being able to reduce the warpage below a desired thresholdamount may permit the die to be successfully processed through thevarious operations, including, by non-limiting example, die bonding, dieattach, package encapsulating, clip attach, lid attach, wire bonding,epoxy dispensing, pin attach, pin insertion, or any other processinvolved in forming a semiconductor package. In various implementationsthe warpage of the die may need to be reduced to less than about 50microns measured across a largest planar surface of the die between ahighest and lowest point on the largest planar surface. In otherimplementations, by non-limiting example, where an assembly processinvolves Au—Si eutectic die attach, the warpage of the die may need tobe reduced to less than about 25 microns when measured across a largestplanar surface of the die. In other implementations, by non-limitingexample, where a die attach process utilizing solder paste is used, thewarpage of the die may need to be reduced to about 75 microns or less.In various implementations, the warpage of the die may be reduced tobelow about 200 microns or less. In implementations where larger die areused, more warpage may be tolerated successfully in subsequent packagingoperations, so while values less than 25 microns may be desirable formany die, depending on die size, more warpage than about 25, than about50, than about 75 microns, or up to about 200 microns may be capable ofbeing tolerated.

In various implementations, the warpage may be measured using varioustechniques. For example, a capacitative scanning system with two probesthat utilize changes in the capacitance for each probe when a die orwafer is inserted into the gap between the probes to determine a waferthickness and/or position can be utilized to map the warpage of a die orwafer. An example of such a capacitive system that may be utilized invarious implementations may be the system marketed under the tradenamePROFORMA 300ISA by MTI Instruments Inc. of Albany, N.Y. In otherimplementations, the warpage may be measured by a laser profilometerutilizing confocal sensors marketed under the tradename ACUITY bySchmitt Industries, Inc. of Portland, Oreg. In other implementations,any of the following shape/profile measurement systems marketed byKeyence Corporation of America of Itasca, Ill. could be employed tomeasure die or wafer warpage: the reflective confocal displacementsensor system marketed under the tradename CL-3000, the 2D laserprofiling system marketed under the tradename LJ-V7000, or the 3Dinterferometric sensing system marketed under the tradename WI-5000.

In the semiconductor device 300 implementation illustrated in FIG. 25,the permanent die support structure 302 is a layer of material coupledto the first largest planar surface 306 of the thinned semiconductor die304. In this implementation, the shape of a perimeter 318 of thepermanent die support structure 302 is substantially the same as theperimeter 316 of the die 304. However, and as described in thisdocument, the shape of the perimeter 318 may be a wide variety ofshapes, including, by non-limiting example, rectangular, triangular,polygonal, elliptical, circular, or any other closed shape. Furthermore,the permanent die support structure 302 may include two or moreportions, which will be described in this document.

In the implementation illustrated in FIG. 25, the permanent die supportstructure includes a mold compound that is applied to the first largestplanar surface 306 of the thinned semiconductor die 304. The moldcompound reduces the warpage of the thinned semiconductor die in any ofa wide variety of ways, such as, by non-limiting example, having apredetermined hardness value, having a predetermined stiffness value,having a predetermined Shore value, having a predetermined glasstransition temperature, having a predetermined cure strength, having apredetermined thickness, having a predetermined film stress, curing at aparticular temperature, curing with a particular temperature rampprofile, curing using specific light wavelengths, including one or morefillers, including one or more resins, or any other compound formationprocess parameter, mold compound ingredient, film parameter capable ofaffecting the warpage of the thinned semiconductor die. While a singlelayer of mold compound is illustrated as being used as the permanent diesupport in FIG. 25, in other implementations two or more layers of moldcompound may be employed to form the die support which contain eitherthe same or different material compositions. These two or more layersmay be applied simultaneously or sequentially in variousimplementations.

In various implementations, the mold compound is not a polyimidematerial or other material generally specifically used to act as apassivating material for a semiconductor die surface. The mold compoundmay include any of a wide variety of compounds, including, bynon-limiting example, encapsulants, epoxies, resins, polymers, polymerblends, fillers, particles, thermally conductive particles, electricallyconductive particles, pigments, and any other material capable ofassisting in forming a stable permanent supporting structure. In someimplementations the mold compound may be non-electrically conductive(insulative). In other implementations, the mold compound may beelectrically conductive, such as an anisotropic conductive film. In suchimplementations where the mold compound is electrically conductive, themold compound is not a metal, but rather is formed as a matrixcontaining electrically conductive materials, such as, by non-limitingexample, metal particles, graphene particles, graphite particles, metalfibers, graphene fibers, carbon fibers, carbon fiber particles, or anyother electrically conductive particle or fiber. In variousimplementations, the mold compound may be a material which has aflexural strength of between about 13 N/mm² to 185 N/mm². Flexuralstrength is the ability of the mold compound to resist plasticdeformation under load. Plastic deformation occurs when the moldcompound no longer will return to its original dimensions afterexperiencing the load. For those implementations of permanent diesupport structures, flexural strength values of the mold compound to beused may generally be selected so that the chosen mold compound hassufficient flexural strength at the maximum expected operatingtemperature to avoid plastic deformation.

A wide variety of shapes and structures may be employed as permanent diesupport structures in various implementations that may employ any of thematerial types, material parameters, or film parameters disclosed inthis document. Referring to FIG. 26, a second implementation of apermanent die support structure 320 that is coupled at the thickness 324of a semiconductor die 322. In this implementation, the permanent diesupport structure 320 extends continuously around thethickness/perimeter 324 of the die 322. In this implementation, havingthe permanent die support structure 320 around the thickness 324 of thedie 322 may reduce the warpage of the die 322 to a desired level likeany disclosed in this document.

While in the implementation illustrated in FIG. 25 the permanent diesupport structure 302 is illustrated coupled with the upper largestplanar surface 306 of the die 304, in other implementations, like thethird one illustrated in FIG. 27, the permanent die support structure326 is coupled to the lower largest planar surface 328 of the die 330.In this implementation, the permanent die support 326 is a layer coupledto the lower largest planar surface 328 and is also substantiallycoextensive with the perimeter 322 of the lower largest planar surface328.

Referring to FIG. 28, a fourth implementation of a permanent die supportstructure 332 is illustrated that includes two C-shaped or U-shapedportions, a first portion 334 and a second portion 336. The firstportion 334 and second portion 336 are separated by a gap along eachside of the semiconductor die 338. The material of the die supportstructure 322 in this implementation is included in the first portion334 and second portion 336 and may be any material disclosed for use ina permanent die support structure disclosed in this document. The fifthimplementation of a permanent die support structure 340 illustrated inFIG. 29 also includes U- or C-shaped first portion 342 and secondportion 344, except that these portions are coupled across or over thethickness 346 of the semiconductor die 348. In other implementations,like the sixth implementation of a permanent die support structure 350illustrated in FIG. 30, the U- or C-shaped first portion 352 and secondportion 354 are coupled to the lower largest planar surface 356 of thesemiconductor die 358 rather than the upper largest planar surface as inthe implementation illustrated in FIG. 28.

Referring to FIG. 31, a seventh implementation of a permanent diesupport structure 360 is illustrated. In this implementation, thestructure 360 is formed of two intersecting lines of material, which areillustrated to be asymmetric in at least one axis. In otherimplementations, however, the shape of the permanent die supportstructure 360 may be symmetric about one or all axes. The location alongthe upper or lower planar surfaces of the semiconductor die 362 at whichthe structure 360 is coupled to the die 364 may be determined bycalculations based on, by non-limiting example, die size, die surfacearea, die shape, localized film properties, localized stress gradients,location(s) of semiconductor devices on/within the die, die thickness,die thickness uniformity, and any other parameter affecting the warpageof a semiconductor die. Also, in this implementation of a permanent diesupport structure 360, the length, orientation, and or position of eachof the projections 366, 368, 370, 372 of the structure 360 may becalculated and/or determined using any of the previously mentionedparameters affecting the warpage of the die 364. FIG. 32 illustrated aneighth implementation of a permanent die support 374, which like thesupport 360 illustrated in FIG. 31 is X-shaped, but which has adifferent side wall profile having rounded side walls rather thanstraight or substantially straight side walls. In variousimplementations, the side wall profile of the permanent die support 374may also be calculated/determined using any of the previously mentionedparameters that affect the warpage of the die 376.

Referring to FIG. 33, a ninth implementation of a permanent die support378 is illustrated which takes the form of a rod/long rectangle withstraight or substantially straight side walls. As previously discussed,the profile of the side walls 384, 386 may be changed to assist inreducing the warpage of the die 380 as can the location of the support378 and its orientation relative to the perimeter 382 of the die 380. Invarious implementations, the rod may not be straight, but may be curvedin one or more places to form, by non-limiting example, a C-shape, aU-shape, an S-shape, an N-shape, a M-shape, a W-shape, or any othercurved or angled shape formed from one continuous piece of material.

Referring to FIG. 34, a tenth implementation of a permanent die support388 is illustrated which contains a central portion 390 from which aplurality of ribs 392 project. The number, location, and position of theribs 392 along the central portion 390 may be determined/calculatedusing any of the previously discussed parameters that affect the warpageof the die 394. The side wall profile of any or all of the ribs 392and/or the central portion 390 may also be calculated in a similar wayusing the previously discussed parameters.

In various implementations, the permanent die support need not be ashape with straight edges/lines, but, like the eleventh implementationof a permanent die support 396 illustrated in FIG. 35, may include anelliptical or spherical shape. In this implementation, the overallthree-dimensional shape of the die support 396 is dome-shaped as theside wall profile of the support is rounded. In other implementations,however, the overall three-dimensional shape of the support 396 may be,by non-limiting example, cylindrical with straight side walls, conicalwith angled side walls, frustoconical with straight side walls and aflat upper surface, or any other three dimensional shape that is formedby projecting an elliptical cross-sectional shape upward from thesurface of die 398.

Referring to FIG. 36, a twelfth implementation of a permanent diesupport 400 that is triangular is illustrated. For those supports 400that are triangular, the shape of the triangle may be acute, right,obtuse, equilateral, isosceles, or scalene in various implementations.As in the previously discussed, the side wall profile of the triangleand the placement of the permanent die support 400 along the largestplanar surface 404 of the semiconductor die 402 may be determined by anyof the previously mentioned parameters that affect the warpage of thedie 402.

In various implementations, the permanent die support can include morethan one portion that is not directly attached to any other portion.Referring to FIG. 37, a thirteenth implementation of a permanent diesupport 406 with a first portion 408 and a second portion 410 that areseparately coupled to the largest planar surface 412 of semiconductordie 414. In this implementation, the specific placement, sizing, andside wall profile of each of the portions 408, 410 may be determined byany of the previously mentioned parameters affecting warpage of the die414. While in the permanent die support 406 implementation illustratedin FIG. 37, the first portion 408 and second portion 410 are coupled tothe largest planar surface 412, in other implementations, as illustratedin FIGS. 38, 41, 42, 43, and 44, the different portions may be coupledon/at the thickness of the semiconductor die. FIG. 38 illustrates afourteenth implementation of a permanent die support 416 that includesfirst, second, third, and fourth portions 418, 420, 422, and 424,respectively coupled around each corner of the semiconductor die 426 atthe thickness 428 of the die. FIG. 41 illustrates a seventeenthimplementation of a permanent die support structure 430 that alsoincludes 4 portions 432, 434, 436, and 438 but which are coupled at thethickness 440 at the midpoint of each side of the semiconductor die 442.While the portions of the permanent die support structures illustratedin FIGS. 37, 38, and 41 are rectangular, in other implementations, theportions may take a variety of other shapes. Referring to FIG. 42, aneighteenth implementation of a permanent die support structure 444 withfour portions 446, 448, 450, and 452 each with a semicircular shape eachcoupled along the entire side of the semiconductor die 454 isillustrated. FIG. 43 illustrates a nineteenth implementation of apermanent die support structure 456 that has a first portion 458 and asecond portion 460 that each are coupled at the thickness along anentire length of two sides of the semiconductor die 462 and then to eachother at two points. In FIG. 43, the die 462 is shaped like aparallelogram. In the implementation illustrated in FIG. 44, thesemiconductor die 464 is triangular and the permanent die supportstructure 466 illustrated includes three triangularly shaped portions468, 470, and 472 which are each triangularly shaped as well and coupledat the thickness along a side of the die 464. In all of theseimplementations of permanent die supports which are coupled at thethickness at or along a side of the die, the dimensions and materials ofthe supports may be selected using any of the previously mentionedparameters that affect the warpage of the die.

In other implementations of permanent die supports coupled on/at thethickness of the die, only a single portion may be utilized. Referringto FIG. 39, a fifteenth implementation of a permanent die support 474 isillustrated that is coupled on the thickness of semiconductor die 478and extends fully along one side 476 of die 478 and contains a portionthat wraps around corner 480 of the die. In this implementation, thelength of the portion that wraps around the corner 480 may be determinedby the degree to which warpage on that side/corner/edge of the die 478needs to be minimized in various implementations. In otherimplementations, referring to FIG. 40, a sixteenth implementation of apermanent die support 482 is illustrated coupled along only one side ofdie 482 at the thickness of the die. The extent to which the permanentdie supports extend along the die sides and around corners may depend onany of the previously mentioned parameters that affect the warpage ofthe die. In other implementations, more than one a single portion thatextends along just one side of the die at the thickness may be employedsuch as portions on alternate sides of the die, portions on three sidesof the die, or portions on two sides of the die.

In various implementations of permanent die supports like thosedisclosed herein, the permanent die support material 494 may fullyenclose both of the largest planar surfaces 488, 490 and the thickness486 of a semiconductor die 492, as illustrated in FIG. 45. Whether thedie support fully encloses all six sides of the die (in the case of arectangular die) depends on the desired warpage values. In suchimplementations where the permanent die support 494 completely coversone or more sides of the die, one or more openings may be providedin/formed in the permanent die support through the material of thepermanent die support 494 to allow electrical or physical connectionswith the die. In various other implementations, the permanent diesupport material 496 may extend over the thickness 498 and one of thetwo largest planar surfaces 500 of the semiconductor die 502. In suchimplementations, electrical and physical connections made be formed viathe exposed largest planar surface 504 and/or through openings in thematerial 496 of the permanent die support. A wide variety of possibleconfigurations may be constructed to form electrical and physicalconnections with the semiconductor die to which a permanent die supportlike any disclosed in this document using the principles disclosedherein. In various implementations, the permanent die support materialmay be conformal, or conform to the shape of the die over which thematerial is coupled. In other implementations, the die support materialmay be non-conformal forming its own shape rather than assuming part ofthe shape of the die. In various implementations, the permanent diesupport material may be applied as a coating to the semiconductor die.

The various implementations of permanent die support structuresdisclosed herein may be formed using various methods of forming a diesupport structure. In a particular method implementation, the methodincludes permanently coupling a material with a semiconductor die. Thismaterial may be a mold compound or any other material disclosed in thisdocument used to form a permanent die support structure. Thesemiconductor die may be any type disclosed herein that includes twolargest planar surfaces with a thickness between the surfaces and thethickness may be any thickness disclosed in this document. Thesemiconductor device(s) included on the semiconductor die may be anydisclosed in this document. At the time where the material ispermanently coupled with the semiconductor die, the material may becoupled with any, all, or any combination of a first largest planarsurface, a second largest planar surface, or the thickness. The methodincludes reducing a warpage of the semiconductor die to less than 50microns through the coupling the material. In particular implementationsthe method may include reducing a warpage of the semiconductor die toless than 25 microns.

As disclosed in this document, in various method implementations, themethod includes permanently coupling two or more portions of material tothe semiconductor die to one, all, or any combination of the firstlargest planar surface, the second largest planar surface, or thethickness. In various method implementations, the method may includepermanently or temporarily coupling a second layer of material over thematerial originally permanently coupled with the semiconductor die.Additional layers beyond the second layer may also be coupled over thesecond layer in various method implementations.

In various method implementations, the point in a semiconductor die'sprocessing where the permanent die support structure is coupled may varyfrom implementation to implementation. In some method implementations,the point at where the permanent die support structure is applied mayoccur before or after the semiconductor die has been physicallysingulated from among the plurality of semiconductor die being formed onthe semiconductor substrate.

For example, referring to FIG. 47, a side view of a semiconductorsubstrate 506 is illustrated with a plurality of die 508 formedthereon/therein. At this point in an implementation of a method of waferscale packaging the plurality of die 508, partial grooves 510 have beenformed between the die 508 using any process disclosed in this documentfor forming such partial grooves 510. Following forming of the partialgrooves 510 (or prior to, in some method implementations), a pluralityof permanent die support structures 512 have been coupled over each ofthe die 508. Subsequent to application of the permanent die supportstructures 512, the method implementation may proceed with variousadditional processing steps like those disclosed in this document,including, by non-limiting example, applying a mold compound over thepermanent die support structures 512; backgrinding the semiconductorsubstrate 506 to thin the thickness of the substrate 506 until thebottom surface of the partial grooves 510 is reached, thus singulatingeach of the die 508 among the plurality of die; and/or singulating thedie using, by non-limiting example, a sawing process, a laseringprocess, a jet ablation process, a wet etching process, a plasma etchingprocess, or any combination thereof. Many additional sequences of methodsteps that incorporate permanent die support structures may be devisedusing the principles disclosed in this document.

In various method implementations, the permanent die support structuremay be employed before any singulation processes have been carried onfor the plurality of die (or at an intermediate step while the substratestill remains in physical form). Referring to FIG. 48, a plurality ofpermanent die support structures 512 are illustrated distributed acrossa semiconductor substrate that takes the form of a wafer 514. In thisimplementation, the permanent die support structures are aligned, oneper die, as illustrated in the detail view of the single die 518 in FIG.49. As illustrated in FIG. 50, the thickness of this the permanent diesupport structure 512 varies across the structure, thinner at the centerand becoming thicker at the edges. In various implementations, thevarying nature/location of the thickness of the structure 512 may bedetermined by any of the previously mentioned parameters that affect thewarpage of the die.

In various method implementations, the permanent die support may becoupled prior to or after probing of the individual die. Similarly, thepermanent die supports may be applied to a plurality of die on asemiconductor substrate prior to or after probing the plurality of die.

In various method implementations, no precut or partial grooving betweenthe plurality of die of a semiconductor substrate may be carried out.Where the plurality of die will be thinned, the depth of the die/sawstreets/scribe lines may be sufficient to carry out the various methodsof forming semiconductor packages disclosed herein. For example, andwith reference to FIG. 51, where the substrate 520 will be thinned toabout 10 microns, the about 5 micron depth of the die streets 524 intothe material of the substrate/die resulting from the processing stepsthat form the plurality of semiconductor die 522 suffices to act as theequivalent of any partial grooving/precutting. In particular methodimplementations, the depth of the die streets can be increased duringthe die fabrication process. In other particular method implementations,the depth of the die streets may be increased during diepreparation/packaging processes following die fabrication. In this way,any separate precut or partial grooving of the wafer using a saw orother process may be rendered unnecessary. Avoiding separatelyprecutting/partial grooving may facilitate the sawing process and/oreliminate risk of sidewall cracking due to coefficient of thermalexpansion (CTE) mismatches. While using the depth of the die streets toset sidewall coverage of mold compound rather than the depth of a precutinto the semiconductor substrate may reduce the partial sidewallcoverage for each die 522 of the plurality of die, the benefits mayoutweigh the additional coverage in various method implementations.

In various method implementations, permanent die support structures maybe coupled to the plurality of die while the semiconductor substratewhile it is at full thickness, or, in other words, prior to any thinningoperations being performed. FIG. 52 illustrates a semiconductorsubstrate 526 with a plurality of die 528 formed thereon with aplurality of permanent die support structures 530 coupled thereto.Additional thinning operations can then be initiated with the permanentdie support structures 530 in place. Also, for those processes whereprecut/grooving operations take place prior to thinning, these steps cantake place after coupling of the permanent die support structures.

In various method implementations, the permanent die support structures536 may be coupled over the die 534 after thinning is performed, asillustrated in the semiconductor substrate 532 of FIG. 53. In otherimplementations, the permanent die support structures 538 may be appliedover the die 540 after backmetal layer(s) 542 have been applied to thesemiconductor substrate 544, as illustrated by the structure in FIG. 54.In yet other method implementations, the permanent die supportstructures 546 may be applied over the plurality of die 548 after thesemiconductor substrate 550 has been only partially thinned, such as, bynon-limiting example, through removing backside oxide prior to probing,an initial grinding step prior to a polishing/lapping step, or any otherprocess which partially removes a layer of material or bulk materialfrom the side 552 of the semiconductor substrate opposite the die 548.

In various method implementations, the permanent die support structures554 may be applied over the plurality of semiconductor die 556 after afull backgrinding process is carried out but prior to or after a stressrelief wet etching process has been carried out, as illustrated in FIG.56. In such implementations, the stress relief wet etching may becarried out with or without backmetal. In some implementations, thestress relief wet etching make take place after protecting the frontside (die side) of the semiconductor substrate. The stress reliefetching may reduce the backside damage to the semiconductor substratethat is caused by the backgrinding process. The use of the stress reliefetching may also facilitate adhesion of the backmetal applied to theground surface. In various implementations, the application of thepermanent die support structures may be carried out prior to a backmetalformation process. A wide variety of sequences of method steps involvingcoupling of permanent die support structures may be carried out usingthe principles disclosed in this document for packaging processinvolving wafer scale operations like those disclosed in this documentused for semiconductor substrates.

Similarly to the timing of applying permanent die support structuresduring methods of wafer scale packaging a plurality die, the timing mayvary in various implementations of chip scale packaging a die. Forexample, the permanent die support structure may be applied as the firststep following die picking from a singulation tape, or immediatelyfollowing die singulation prior to picking. In other methodimplementations, the permanent die support structure may be applied at alater step in the process, such as, by non-limiting example, die attach,die underfilling, flux washing, epoxy cure, prior to a fullencapsulating step, after lead frame attach, or any other chip scalepackaging process operation. A wide variety of sequences of method stepsinvolving coupling a permanent die support structure may be employed invarious method implementations using the principles disclosed in thisdocument.

In various semiconductor package and method implementations disclosed inthis document, any of the pads or electrical connectors disclosed inthis document may be formed, by any or any combination of the following:evaporation, sputtering, soldering together, screen printing, solderscreen printing, silver sintering one or more layers of materials. Anyof the foregoing may also be used in combination with electroplating orelectroless plating methods of forming pads and/or electricalconnectors.

Referring to FIG. 57, an implementation of a thinned semiconductor die558 is illustrated. Various implementations of thinned semiconductor diedisclosed in this document may be formed from a wide variety ofsemiconductor substrate types, including, by non-limiting example,silicon, polysilicon, silicon-on-insulator, glass, sapphire, ruby,gallium arsenide, silicon carbide, and any other semiconductor materialtype. Also, various implementations of thinned semiconductor die mayinclude die of any of a wide variety of shapes, including, bynon-limiting example, rectangular, elliptical, triangular, polygonal, orany other closed shape. The various implementations of thinnedsemiconductor die disclosed herein may include any of a wide variety ofelectronic devices, including, by non-limiting example, integratedbipolar junction transistors (IGBTs), metal oxide semiconductor fieldeffect transistors (MOSFETs), diodes, power semiconductor devices, anysemiconductor device disclosed in this document, any combinationthereof, or any other active or passive semiconductor device orcomponent, alone or in combination. As illustrated, the die 558 has afirst largest planar surface 560 and a second largest planar surface 562with thickness 564 between them. Because the die 558 is a rectangulardie, four additional sides 566, 568, 570, and 572 extend across thethickness 564.

In various implementations disclosed herein, the thickness 564 of thethinned semiconductor die may be between about 0.1 microns and about 125microns. In other implementations, the thickness may be between about0.1 microns and about 100 microns. In other implementations, thethickness may be between about 0.1 microns and about 75 microns. Inother implementations, the thickness may be between about 0.1 micronsand about 50 microns. In other implementations, the thickness may bebetween about 0.1 microns and about 25 microns. In otherimplementations, the thickness may be between about 0.1 microns andabout 10 microns. In other implementations, thickness may be between 0.1microns and about 5 microns. In other implementations, the thickness maybe less than 5 microns.

The various semiconductor die disclosed herein may include various diesizes. Die size generally refers to measured principal dimensions of theperimeter of the die. For example, for a rectangular die that is asquare, the die size can be represented by referring to a height andwidth (length and width) of the perimeter. In various implementations,the die size of the semiconductor die may be at least about 4 mm byabout 4 mm where the perimeter of the die is rectangular. In otherimplementations, the die size may be smaller. In other implementations,the die size of the semiconductor die may be about 211 mm by about 211mm or smaller. For die with a perimeter that is not rectangular, thesurface area of the largest planar surface of die may be used as arepresentation of the die size.

One of the effects of thinning the semiconductor die is that as thethickness decreases, the largest planar surfaces of the die may tend towarp or bend in one or more directions as the thinned material of thedie permits movement of the material under various forces. Similarwarping or bending effects may be observed where the die size becomesmuch larger than the thickness of the die for large die above about 6 mmby about 6 mm or 36 mm² in surface area. These forces include tensileforces applied by stressed films, stress created through backgrinding,forces applied by backmetal formed onto a largest planar surface of thedie, and/or forces induced by the structure of the one or more devicesformed on and/or in the semiconductor die. This warping or bending ofthe thinned semiconductor die can prevent successful processing of thedie through the remaining operations needed to form a semiconductorpackage around the die to allow it to ultimately function as, bynon-limiting example, a desired electronic component, processor, powersemiconductor device, switch, or other active or passive electricalcomponent. Being able to reduce the warpage below a desired thresholdamount may permit the die to be successfully processed through thevarious operations, including, by non-limiting example, die bonding, dieattach, package encapsulating, clip attach, lid attach, wire bonding,epoxy dispensing, pin attach, pin insertion, or any other processinvolved in forming a semiconductor package. In various implementationsthe warpage of the die may need to be reduced to less than about 50microns measured across a largest planar surface of the die between ahighest and lowest point on the largest planar surface.

In other implementations, by non-limiting example, where an assemblyprocess involves Au—Si eutectic die attach, the warpage of the die mayneed to be reduced to less than about 25 microns when measured across alargest planar surface of the die. In other implementations, bynon-limiting example, where a die attach process utilizing solder pasteis used, the warpage of the die may need to be reduced to about 75microns or less. In various implementations, the warpage of the die maybe reduced to below about 200 microns or less. In implementations wherelarger die are used, more warpage may be tolerated successfully insubsequent packaging operations, so while values less than 25 micronsmay be desirable for many die, depending on die size, more warpage thanabout 25, than about 50, than about 75 microns, or up to about 200microns may be capable of being tolerated.

In various implementations, the warpage may be measured using varioustechniques. For example, a capacitative scanning system with two probesthat utilize changes in the capacitance for each probe when a die orwafer is inserted into the gap between the probes to determine a waferthickness and/or position can be utilized to map the warpage of a die orwafer. An example of such a capacitive system that may be utilized invarious implementations may be the system marketed under the tradenamePROFORMA 300ISA by MTI Instruments Inc. of Albany, N.Y. In otherimplementations, the warpage may be measured by a laser profilometerutilizing confocal sensors marketed under the tradename ACUITY bySchmitt Industries, Inc. of Portland, Oreg. In other implementations,any of the following shape/profile measurement systems marketed byKeyence Corporation of America of Itasca, Ill. could be employed tomeasure die or wafer warpage: the reflective confocal displacementsensor system marketed under the tradename CL-3000, the 2D laserprofiling system marketed under the tradename LJ-V7000, or the 3Dinterferometric sensing system marketed under the tradename WI-5000.

Referring to FIG. 58, an implementation of a temporary die supportstructure (temporary die support) 574 is illustrated coupled to asemiconductor die 576. In this implementation, the temporary die support574 is coupled to and coextensive with a perimeter 578 of a largestplanar surface 580 of the die 576. However, and as described in thisdocument, the shape of the perimeter 578 may be a wide variety ofshapes, including, by non-limiting example, rectangular, triangular,polygonal, elliptical, circular, or any other closed shape. Thetemporary die support structure works to support the die during diepackaging operations. Furthermore, the temporary die support structure574 may include two or more portions, which will be described in thisdocument.

In the implementation illustrated in FIG. 58, the temporary die supportstructure includes a material that is applied to the first largestplanar surface 580 of the thinned semiconductor die 576. The materialreduces the warpage of the thinned semiconductor die in any of a widevariety of ways, such as, by non-limiting example, having apredetermined hardness value, having a predetermined stiffness value,having a predetermined Shore value, having a predetermined glasstransition temperature, having a predetermined cure strength, having apredetermined thickness, having a predetermined film stress, curing at aparticular temperature, curing with a particular temperature rampprofile, curing using specific light wavelengths, including one or morefillers, including one or more resins, or any other compound formationprocess parameter, mold compound ingredient, film parameter capable ofaffecting the warpage of the thinned semiconductor die. While a singlelayer of material is illustrated as being used as the temporary diesupport in FIG. 58, in other implementations two or more layers ofmaterial may be employed to form the die support which contain eitherthe same or different material compositions. These two or more layersmay be applied simultaneously or sequentially in variousimplementations.

A wide variety of forms of materials may be employed in variousimplementations of temporary die supports, including, by non-limitingexample, a coating (which may be applied, by non-limiting example,through painting, sputtering, evaporating, electroplating, electrolessplating, or spraying or any other method of coating), a tape, a film, aprinted structure, a screen printed structure, a stencil printedstructure, an adhesive bonded structure, or any other material formcapable of being removably or releaseably coupled with the surface of asemiconductor die. A wide variety of material types may be employed invarious implementations of temporary die supports, including, bynon-limiting example, polyimides, polybenzoxazoles, polyethylenes,metals, benzocyclobutenes (BCBs), photopolymers, adhesives, and anyother material or combination of materials capable of being removably orreleaseably coupled with a semiconductor die.

A wide variety of shapes and structures may be employed as temporary diesupport structures in various implementations that may employ any of thematerial types, material forms, material parameters, or film parametersdisclosed in this document to reduce the warpage of a thinned die to anyof the desired levels disclosed in this document. In variousimplementations, the flexural strength of the temporary die supportmaterial may be a factor to be considered. Flexural strength is theability of the temporary die support material to resist plasticdeformation under load. Plastic deformation occurs when the temporarydie support material no longer will return to its original dimensionsafter experiencing the load.

Referring to FIG. 59, an implementation of a temporary die support 582is illustrated after a first layer 584 has been applied to the largestplanar surface 586 of semiconductor die 588. A second layer 590 isillustrated being coupled over the first layer 584. In variousimplementations, the materials of the first layer 584 and the secondlayer 590 may be the same or different. Also, in some implementations,the first layer 584 may be remain permanently coupled to the die 588 asa permanent die support structure while just the second layer 590 isremovable therefrom. In other implementations, however, both the firstlayer 584 and the second layer 590 are removable or releasable from thedie 588.

Referring to FIG. 60, an implementation of a temporary die supportstructure 592 is illustrated that includes two C-shaped or U-shapedportions, a first portion 594 and a second portion 596. The firstportion 594 and second portion 596 are separated by a gap along eachside of the semiconductor die 598. The material of the die supportstructure 592 in this implementation is included in the first portion594 and second portion 596 and may be any material disclosed for use ina temporary die support structure disclosed in this document. While thefirst portion 594 and second portion 596 are coupled to a top largestplanar surface 598 of the die 600, in other implementations, they may becoupled to a bottom largest planar surface 602. In otherimplementations, the U- or C-shaped first portion 594 and second portion596 are coupled just across or over the thickness 602 of thesemiconductor die 600.

Referring to FIG. 61, an implementation of a temporary die supportstructure 604 is illustrated. In this implementation, the structure 604is formed of two intersecting lines of material, which are illustratedto be asymmetric in at least one axis. In other implementations,however, the shape of the temporary die support structure 604 may besymmetric about one or all axes. The location along the upper or lowerplanar surfaces of the semiconductor die 606 at which the structure 604is coupled to the die 606 may be determined by calculations based on, bynon-limiting example, die size, die surface area, die shape, localizedfilm properties, localized stress gradients, location(s) ofsemiconductor devices on/within the die, die thickness, die thicknessuniformity, and any other parameter affecting the warpage of asemiconductor die. Also, in this implementation of a temporary diesupport structure 604, the length, orientation, and or position of eachof the projections 608, 610, 612, 614 of the structure 604 may becalculated and/or determined using any of the previously mentionedparameters affecting the warpage of the die 606. In otherimplementations of a temporary die may be X-shaped, but have a differentside wall profile having rounded side walls rather than straight orsubstantially straight side walls. In various implementations, the sidewall profile of the temporary die support 604 may also becalculated/determined using any of the previously mentioned parametersthat affect the warpage of the die 606.

Referring to FIG. 62, an implementation of a temporary die support 616is illustrated which takes the form of a rod/long rectangle withstraight or substantially straight side walls. As previously discussed,the profile of the side walls 618, 620 may be changed to assist inreducing the warpage of the die 622 as can the location of the support616 and its orientation relative to the perimeter 624 of the die 622. Invarious implementations, the rod may not be straight, but may be curvedin one or more places to form, by non-limiting example, a C-shape, aU-shape, an S-shape, an N-shape, a M-shape, a W-shape, or any othercurved shape formed from one continuous piece of material.

Referring to FIG. 63, an implementation of a temporary die support 626is illustrated which contains a central portion 628 from which aplurality of ribs 630 project. The number location, and position of theribs 630 along the central portion 628 may be determined/calculatedusing any of the previously discussed parameters that affect the warpageof the die 632. The side wall profile of any or all of the ribs 630and/or the central portion 628 may also be calculated in a similar wayusing the previously discussed parameters.

In various implementations, the temporary die support need not be ashape with straight edges/lines, but, like the implementation of atemporary die support 634 illustrated in FIG. 64, may include anelliptical or spherical shape. In this implementation, the die support634 is in the shape of an oval ring. In other implementations, however,as illustrated in FIG. 70, the overall three-dimensional shape of thedie support 636 is dome-shaped as the side wall profile of the support636 is rounded. In other implementations, however, the overallthree-dimensional shape of the support 636 may be, by non-limitingexample, cylindrical with straight side walls, conical with angled sidewalls, frustoconical with straight side walls and a flat upper surface,or any other three dimensional shape that is formed by projecting anelliptical cross-sectional shape upward from the surface of die 638.

Referring to FIG. 65, an implementation of a temporary die support 640that is triangular is illustrated. For those supports 640 that aretriangular, the shape of the triangle may be acute, right, obtuse,equilateral, isosceles, or scalene in various implementations. As in thepreviously discussed, the side wall profile of the triangle and theplacement of the temporary die support 640 along the largest planarsurface 642 of the semiconductor die 644 may be determined by any of thepreviously mentioned parameters that affect the warpage of the die 644.

In various implementations, the temporary die support can include morethan one portion that is not directly attached to any other portion.Referring to FIG. 66, an implementation of a temporary die support 646with a first portion 648 and a second portion 650 that are separatelycoupled to the largest planar surface 652 of semiconductor die 654. Inthis implementation, the specific placement, sizing, and side wallprofile of each of the portions 648, 650 may be determined by any of thepreviously mention parameters affecting warpage of the die 654. While inthe temporary die support 646 implementation illustrated in FIG. 66, thefirst portion 648 and second portion 650 are coupled to the largestplanar surface 652, in other implementations, the different portions maybe coupled on/at the thickness of the semiconductor die or on differentsides of the die 654.

In other implementations of temporary die supports coupled on/at thethickness of the die, only a single portion may be utilized. Referringto FIG. 69, an implementation of a temporary die support 656 isillustrated that is coupled on the thickness 658 of semiconductor die660 and extends fully along one side 662 of die 660 and contains aportion that wraps around corner 664 of the die. In this implementation,the length of the portion that wraps around the corner 664 may bedetermined by the degree to which warpage on that side/corner/edge ofthe die 660 needs to be minimized in various implementations. In otherimplementations, referring to FIG. 67, an implementation of a temporarydie support 666 is illustrated coupled along only one side 668 of die670 at the thickness 672 of the die 670. The extent to which thetemporary die supports extend along the die sides and around corners maydepend on any of the previously mentioned parameters that affect thewarpage of the die. In other implementations, more than one a singleportion that extends along just one side of the die at the thickness maybe employed such as portions on alternate sides of the die, portions onthree sides of the die, or portions on two sides of the die.

FIG. 68 illustrates an implementation of a temporary die support 674that includes first and second portions 676, 678 respectively coupledaround two corners of the semiconductor die 680 at the thickness 682 ofthe die. In other implementations, a temporary die support structurecould also include two portions coupled at the thickness at the midpointof each side of a semiconductor die. While the portions of the temporarydie support structures illustrated in FIGS. 67 and 68 are rectangular,in other implementations, the portions may take a variety of othershapes. For example, the portions could take on a semicircular shapeeach coupled along the entire side of the semiconductor die. In otherimplementations, the temporary support structure could be coupled at thethickness along an entire length of two sides of the semiconductor dieand then to each other at two points. Where the semiconductor die istriangular, the temporary die support structure may include threetriangularly shaped portions each triangularly shaped as well coupled atthe thickness along a side of the die. In all of these implementationsof temporary die supports which are coupled at the thickness at or alonga side of the die, the dimensions and materials of the supports may beselected using any of the previously mentioned parameters that affectthe warpage of the die.

Referring to FIG. 71, in various implementations of temporary diesupports like those disclosed herein, the temporary die support material684 may enclose one, both, or partially fully enclose both of thelargest planar surfaces 686, 688 and the thickness 670 of asemiconductor die 672. In the implementation illustrated in FIG. 71, thelargest planar surface 688 and the surfaces on the thickness 670 areenclosed. Since the temporary die support is intended to beremovably/releaseably coupled with the die, generally the die supportdoes not fully encloses all six sides of the die (in the case of arectangular die). However, in some implementations where the temporarydie support can be sequentially etched prior to and after die bonding,fully enclosing temporary die supports could potentially be used. Thenumber of sides covered/partially covered by the temporary die supportdepends on the desired warpage values. In some implementations where thetemporary die support 684 completely covers one or more sides of thedie, one or more openings may be provided in/formed in the temporary diesupport through the material of the temporary die support 684 to allowelectrical or physical connections with the die. In variousimplementations, the temporary die support material may be conformal, orconform to the shape of the die over which the material is coupled, asillustrated by the temporary die support 674 of FIG. 72. In otherimplementations, the die support material may be non-conformal orpartially non-conformal forming its own shape rather than assuming partof the shape of the die as in the temporary die support 684 of FIG. 71.In various implementations, the temporary die support material may beapplied as a coating to the semiconductor die.

Referring to FIGS. 73 and 74, side views of two implementations oftemporary support structures are illustrated. In FIG. 73, animplementation of a temporary support structure 676 is illustrated thatdoes not coextensive with the perimeter 678 of the largest planarsurface 680 of a semiconductor die 682. In FIG. 74, an implementation ofa temporary support structure 684 with two portions 685, 687 isillustrated indicating their position along the largest planar surface690 of the semiconductor die 692. FIG. 83 illustrates a side view of asemiconductor die 694 with a temporary support structure 696 thatincludes a first layer 698 coupled on one side of the die 694 and asecond layer 700 coupled on a second side of the die 694. The materialsof each of the first layer 698 and 700 may be different from each other,enabling control of the warpage of the die 694 to a desired value. FIG.84 illustrates another implementation of a temporary support structure702 coupled to die 704 where the structure 702 includes two layers, afirst layer 706 coextensive with the perimeter 708 of the die 704 and asecond layer 710 coupled over the first layer 706 and containing anelliptical opening 712 therein. The dimensions, size, and positioning ofopening 712 may be used to allow minimization of the warpage of the die704 to a desired level. While a single elliptical opening in the secondlayer 710 is illustrated, in other implementations, multiple openingsand/or openings with any closed shape may be employed in variousimplementations.

Referring to FIG. 76, a top view of a temporary die support 714 isillustrated that has a first portion 716 and a second portion 718 thatare curved and mirrored with respect to each other. The spacing andradius of curvature of the first portion 716 and second portion 718 maybe varied to assist with controlling the warpage of the die 720. Whilethe first portion 716 and second portion 718 are illustrated as beingsymmetrically arranged on the die 720 and mirrored, in otherimplementations, they may be asymmetrically arranged and/or notmirrored, each with different radiuses of curvature.

Referring to FIG. 77, an implementation of a temporary die supportstructure 722 similar to FIG. 61 is illustrated from a side view, butwhere thickness of the support 722 varies across the support. Here thecenter 724 of the support is thinner than the outer edges 726 of thesupport 722. In various implementations the reverse could be true and inother implementations the thickness may vary regularly or irregularlyacross the temporary support depending upon the desired warping controleffect.

In the various implementations of temporary die support structuresdisclosed herein, a thickness of the support structure may be thickerthan a thickness of the die. Such a situation is illustrated in the sideview in FIG. 85, where the thickness 728 of die 730 is much thinner thanthe thickness 732 of the temporary die support 734. A wide variety ofcombinations of temporary die support thicknesses, layer thicknessesused in temporary die supports, and die thicknesses may be constructedusing the principles disclosed in this document.

The various implementations of temporary die support structuresdisclosed herein may be formed using various methods of forming a diesupport structure. In a particular method implementation, the methodincludes temporarily coupling a material with a semiconductor die. Thismaterial may be any material disclosed in this document used to form atemporary die support structure. The semiconductor die may be any typedisclosed herein that includes two largest planar surfaces with athickness between the surfaces and the thickness may be any thicknessdisclosed in this document. The semiconductor device(s) included on thesemiconductor die may be any disclosed in this document. At the timewhere the material is temporarily coupled with the semiconductor die,the material may be coupled with any, all, or any combination of a firstlargest planar surface, a second largest planar surface, or thethickness. The method includes reducing a warpage of the semiconductordie to less than 50 microns through the coupling the material. Inparticular implementations the method may include reducing a warpage ofthe semiconductor die to less than 25 microns.

As disclosed in this document, in various method implementations, themethod includes temporarily coupling two or more portions of material tothe semiconductor die to one, all, or any combination of the firstlargest planar surface, the second largest planar surface, or thethickness. In various method implementations, the method may includetemporarily coupling a second layer of material over materialpermanently or temporarily coupled with the semiconductor die.Additional layers beyond the second layer may also be coupled over thesecond layer in various method implementations.

In various method implementations, the point in a semiconductor die'sprocessing where the temporary die support structure is coupled may varyfrom implementation to implementation. In some method implementations,the point at where the temporary die support structure is applied mayoccur before or after the semiconductor die has been physicallysingulated from among the plurality of semiconductor die being formed onthe semiconductor substrate.

In various method implementations, the temporary die support structuremay be employed before any singulation processes have been carried onfor the plurality of die (or at an intermediate step while the substratestill remains in physical form). Referring to FIG. 75, a plurality oftemporary die support structures 734 are illustrated distributed acrossa semiconductor substrate that takes the form of a wafer 736. In thisimplementation, the temporary die support structures are aligned, oneper die.

In various method implementations, the temporary die support may becoupled prior to or after probing of the individual die. Similarly, thetemporary die supports may be applied to a plurality of die on asemiconductor substrate prior to or after probing the plurality of die.

In various method implementations, no precut or partial grooving betweenthe plurality of die of a semiconductor substrate may be carried out.Where the plurality of die will be thinned, the depth of the die/sawstreets/scribe lines may be sufficient to carry out the various methodsof forming semiconductor packages disclosed herein. For example, andwith reference to FIG. 86, where the substrate 738 will be thinned toabout 10 microns, the about 5 micron depth of the die streets 740 intothe material of the substrate/die resulting from the processing stepsthat form the plurality of semiconductor die 742 suffices to act as theequivalent of any partial grooving/precutting. In particular methodimplementations, the depth of the die streets can be increased duringthe die fabrication process. In other particular method implementations,the depth of the die streets may be increased during diepreparation/packaging processes following die fabrication. In this way,any separate precut or partial grooving of the wafer using a saw orother process may be rendered unnecessary. Avoiding separatelyprecutting/partial grooving may facilitate the sawing process and/oreliminate risk of sidewall cracking due to coefficient of thermalexpansion (CTE) mismatches. While using the depth of the die streets toset sidewall coverage of mold compound rather than the depth of a precutinto the semiconductor substrate may reduce the partial sidewallcoverage for each die 742 of the plurality of die, the benefits mayoutweigh the additional coverage in various method implementations.

In various method implementations, temporary die support structures maybe coupled to the plurality of die while the semiconductor substratewhile it is at full thickness, or, in other words, prior to any thinningoperations being performed. Additional thinning operations can then beinitiated with the temporary die support structures in place. Also, forthose processes where precut/grooving operations take place prior tothinning, these steps can take place after coupling of the temporary diesupport structures.

In various method implementations, the temporary die support structures208 may be coupled over a plurality of die 746 after thinning isperformed, as illustrated in the semiconductor substrate 748 of FIG. 78.In other implementations, the temporary die support structures 744 maybe applied over the plurality of die 746 after backmetal layer(s) havebeen applied to the semiconductor substrate. In yet other methodimplementations, the temporary die support structures 744 may be appliedover the plurality of die 746 after the semiconductor substrate 748 hasbeen only partially thinned, such as, by non-limiting example, throughremoving backside oxide prior to probing, an initial grinding step priorto a polishing/lapping step, or any other process which partiallyremoves a layer of material or bulk material from the side 750 of thesemiconductor substrate 748 opposite the die 746.

In various method implementations, the temporary die support structures744 may be applied over the plurality of semiconductor die 746 after afull backgrinding process is carried out but prior to or after a stressrelief wet etching process has been carried out. In suchimplementations, the stress relief wet etching may be carried out withor without backmetal. In some implementations, the stress relief wetetching make take place after protecting the front side (die side) ofthe semiconductor substrate. The stress relief etching may reduce thebackside damage to the semiconductor substrate that is caused by thebackgrinding process. The use of the stress relief etching may alsofacilitate adhesion of the backmetal applied to the ground surface. Invarious implementations, the application of the temporary die supportstructures may be carried out prior to a backmetal formation process. Awide variety of sequences of method steps involving coupling oftemporary die support structures may be carried out using the principlesdisclosed in this document for packaging process involving wafer scaleoperations like those disclosed in this document used for semiconductorsubstrates.

Referring to FIG. 79, the temporary die support structures 752 may beapplied to the thinned die 754 after die singulation but before diepicking while the thinned die 754 are still supported on dicing tape756. A wide variety of potential options may exist for the timing ofwhen the temporary support structures may be applied to the die duringwafer scale packaging operations.

Similarly to the timing of applying temporary die support structuresduring methods of wafer scale packaging a plurality die, the timing mayvary in various implementations of chip scale packaging a die. Forexample, the temporary die support structure may be applied as the firststep following die picking from a singulation tape, or immediatelyfollowing die singulation prior to picking. In other methodimplementations, the temporary die support structure may be applied ator just prior to a later step in the process, such as, by non-limitingexample, die attach, die underfilling, flux washing, epoxy cure, priorto a full encapsulating step, after lead frame attach, or any other chipscale packaging process operation. In various implementations, thetemporary die support may generally be applied prior to die attach, asafter die attach there may be no further need for the temporary diesupport. A wide variety of sequences of method steps involving couplinga temporary die support structure may be employed in various methodimplementations using the principles disclosed in this document.

A wide variety of methods and processes may be employed to remove thetemporary die supports from the die at the point in the process wherethe temporary supports are no longer needed. Referring to FIG. 80, animplementation of a temporary die support 758 is being illustrated whilebeing peeled off of the surface of die 760 after or during exposure fromlight source 762. This light source may be, by non-limiting example, avisible light source, an infrared light source, an ultraviolet lightsource, a laser light source, or any other source of light capable ofacting to release or assist in releasing the temporary die support. Forexample, if the temporary die support was a UV release tape, then thesupport could be peeled from the surface of the thinned die followingexposure to a UV light source for a predetermined period of time afterthe thinned die had been attached to, by non-limiting example, asubstrate, leadframe, another die, a lead, a redistribution layer, anycombination thereof, or any other die bonding structure.

Referring to FIG. 81, a temporary die support 764 is illustrated beingetched from a die 766 using a plasma etching source 768. While a plasmaetching source 768 is illustrated in FIG. 81, any other etching processcould be employed in various implementations, including, by non-limitingexample, a wet etching process, a spray etching process, a reactive ionetching process, an ion bombardment process, a lasering process, agrinding process, or any other process capable of reacting away orablating the material of the temporary die support.

In other implementations, the temporary die support may be removed usingenergy assisting processes. Referring to FIG. 82, an implementation of atemporary die support 770 is illustrated separating from thinned die 772in a bath 774 under ultrasonic energy produced by ultrasonic energysource 776. Under the influence of the compression waves in the fluid ofthe bath 774, the temporary die support 770 may separate withoutrequiring any pulling force, or the peeling of the temporary die support770 may be enabled by the ultrasonic energy. While the use of a bath 774is illustrated, in various implementations a puddle may be used. Instill other implementations, the ultrasonic energy may be directly orindirectly applied to the die 772 through a spindle, a chuck, a plate,or a liquid stream. In various implementations, the source of sonicenergy 776 may range from about 20 kHz to about 3 GHz. Where the sonicfrequencies utilized by the ultrasonic energy source 776 are above 360kHz, the energy source may also be referred to as a megasonic energysource. In particular implementations, the sonic energy source 776 maygenerate ultrasonic vibrations at a frequency of 40 kHz at a power of 80W. In various implementations, the sonic energy source 776 may apply afrequency of between about 30 kHz to about 50 kHz or about 35 kHz toabout 45 kHz. However, in various implementations, frequencies higherthan 50 kHz may be employed, including megasonic frequencies. A widevariety of power levels may also be employed in various implementations.

In various semiconductor package and method implementations disclosed inthis document, any of the pads or electrical connectors disclosed inthis document may be formed, by any or any combination of the following:evaporation, sputtering, soldering together, screen printing, solderscreen printing, silver sintering one or more layers of materials. Anyof the foregoing may also be used in combination with electroplating orelectroless plating methods of forming pads and/or electricalconnectors.

Referring to FIG. 87, an implementation of two thinned semiconductor die778 is illustrated. Various implementations of groups of thinnedsemiconductor die disclosed in this document may be formed from a widevariety of semiconductor substrate types, including, by non-limitingexample, silicon, polysilicon, silicon-on-insulator, glass, sapphire,ruby, gallium arsenide, silicon carbide, and any other semiconductormaterial type. Also, various implementations of groups of thinnedsemiconductor die may include die of any of a wide variety of shapes,including, by non-limiting example, rectangular, elliptical, triangular,polygonal, or any other closed shape. The various implementations ofgroups of thinned semiconductor die disclosed herein may include any ofa wide variety of electronic devices, including, by non-limitingexample, integrated bipolar junction transistors (IGBTs), metal oxidesemiconductor field effect transistors (MOSFETs), diodes, powersemiconductor devices, any semiconductor device disclosed in thisdocument, any combination thereof, or any other active or passivesemiconductor device or component, alone or in combination. Asillustrated with reference to FIGS. 87 and 88, the two semiconductor die778 collectively form a first largest planar surface 780 and a secondlargest planar surface 782 with thickness 784 between them. Because theshape formed by the two semiconductor die 778 is a rectangle, fouradditional sides 786, 788, 790, and 792 extend across the thickness 784.

In various implementations disclosed herein, the thickness 784 of thegroups of thinned semiconductor die may be between about 0.1 microns andabout 125 microns. In other implementations, the thickness may bebetween about 0.1 microns and about 100 microns. In otherimplementations, the thickness may be between about 0.1 microns andabout 75 microns. In other implementations, the thickness may be betweenabout 0.1 microns and about 50 microns. In other implementations, thethickness may be between about 0.1 microns and about 25 microns. Inother implementations, the thickness may be between about 0.1 micronsand about 10 microns. In other implementations, thickness may be between0.1 microns and about 5 microns. In other implementations, the thicknessmay be less than 5 microns.

The groups of various semiconductor die disclosed herein may form groupsof various sizes (die sizes). Die size generally refers to measuredprincipal dimensions of the perimeter of the shape formed by aparticular group of semiconductor die. For example, for a group of tworectangular die that collectively have a perimeter shaped like a square,the die size can be represented by referring to a height and width ofthe perimeter. In various implementations, the die size of the group ofsemiconductor die may be at least about 4 mm by about 4 mm where theperimeter of the group of die is rectangular. In other implementations,the die size may be smaller. In other implementations, the die size ofthe group of semiconductor die may be about 211 mm by about 211 mm orsmaller. For a group of die with a perimeter that is not rectangular,the surface area of the largest planar surface of the group of die maybe used as a representation of the die size.

One of the effects of thinning the groups of semiconductor die is thatas the thickness decreases, the largest planar surfaces of the groups ofsemiconductor die may tend to warp or bend in one or more directions asthe thinned material of the die permits movement of the material undervarious forces. Similar warping or bending effects may be observed wherethe die size becomes much larger than the thickness of the die for largegroups of die above about 6 mm by about 6 mm or 36 mm² in surface area.These forces include tensile forces applied by stressed films, stresscreated through backgrinding, forces applied by backmetal formed onto alargest planar surface of the die, and/or forces induced by thestructure of the one or more devices formed on and/or in thesemiconductor die. This warping or bending of the thinned groups ofsemiconductor die can prevent successful processing of the die throughthe remaining operations needed to form a semiconductor package aroundthe die to allow it to ultimately function as, by non-limiting example,a desired electronic component, processor, module, power semiconductordevice, switch, or other active or passive electrical component. Beingable to reduce the warpage below a desired threshold amount may permitthe groups of die to be successfully processed through the variousoperations, including, by non-limiting example, die bonding, die attach,package encapsulating, clip attach, lid attach, wire bonding, epoxydispensing, pin attach, pin insertion, or any other process involved informing a semiconductor package. In various implementations the warpageof the group of die may need to be reduced to less than about 50 micronsmeasured across a largest planar surface of the die between a highestand lowest point on the largest planar surface. In otherimplementations, by non-limiting example, where an assembly processinvolves Au—Si eutectic die attach, the warpage of the group of die mayneed to be reduced to less than about 25 microns when measured across alargest planar surface of the group of die. In other implementations, bynon-limiting example, where a die attach process utilizing solder pasteis used, the warpage of the group of die may need to be reduced to about75 microns or less. In various implementations, the warpage of the groupof die may be reduced to below about 200 microns or less. Inimplementations where larger die are used, more warpage may be toleratedsuccessfully in subsequent packaging operations, so while values lessthan 25 microns may be desirable for many groups of die, depending ondie size, more warpage than about 25, than about 50, than about 75microns, or up to about 200 microns may be capable of being tolerated.

In various implementations, the warpage may be measured using varioustechniques. For example, a capacitative scanning system with two probesthat utilize changes in the capacitance for each probe when a group ofdie or wafer is inserted into the gap between the probes to determine awafer thickness and/or position can be utilized to map the warpage of adie or wafer. An example of such a capacitive system that may beutilized in various implementations may be the system marketed under thetradename PROFORMA 300ISA by MTI Instruments Inc. of Albany, N.Y. Inother implementations, the warpage may be measured by a laserprofilometer utilizing confocal sensors marketed under the tradenameACUITY by Schmitt Industries, Inc. of Portland, Oreg. In otherimplementations, any of the following shape/profile measurement systemsmarketed by Keyence Corporation of America of Itasca, Ill. could beemployed to measure die or wafer warpage: the reflective confocaldisplacement sensor system marketed under the tradename CL-3000, the 2Dlaser profiling system marketed under the tradename LJ-V7000, or the 3Dinterferometric sensing system marketed under the tradename WI-5000.

Referring to FIG. 88, the two semiconductor die are illustrated coupledtogether through die street 794. In such an implementation, the twosemiconductor are formed through singulating all of the die streetsaround the two die except for the one that couples the two die together.As illustrated in FIG. 88, an implementation of a permanent die supportstructure (permanent die support, die support) 796 is illustratedcoupled to the two semiconductor die 778. In this implementation, thedie support 796 is coupled to and coextensive with a perimeter 798 of alargest planar surface 4 of the two semiconductor die 778. However, andas described in this document, the shape of the perimeter 798 may be awide variety of shapes, including, by non-limiting example, rectangular,triangular, polygonal, elliptical, circular, or any other closed shape.The permanent die support structure 18 works to support the twosemiconductor die during die packaging operations. Furthermore, thepermanent die support structure 796 may include two or more portions,which will be described in this document.

In various implementations disclosed in this document, where two or moresemiconductor die are packaged together which are intended to beelectrically isolated from each other, one or more isolation trenchesmay be formed between the two more semiconductor die. These isolationtrenches may take various forms in different implementations. Bynon-limiting example, an isolation trench may be formed by etching orablating a trench structure into the material of the die street betweenthe two more semiconductor die and then filling the trench with anelectrically insulating material, such as, by non-limiting example, anoxide, an organic material, a mold compound, any combination thereof, orany other electrically insulating material. In another non-limitingexample, the isolation trench may be formed by etching or ablating aseries of holes (vias) into the material of the die street between thetwo or more semiconductor die and then filling the vias with anelectrically insulating material like any disclosed herein. A widevariety of isolation trench structures may be formed using theprinciples disclosed herein to ensure electrical isolation betweensemiconductor die that are packaged together while joined by a diestreet region.

While in the implementation illustrated in FIG. 88 the die supportstructure 796 is a permanent die support structure, in otherimplementations of die support structures disclosed in this document,the die supports structures may be temporary. Referring to FIG. 89, animplementation of a temporary die support structure 800 coupled to anupper planar surface 802 of a group 804 of two semiconductor die isillustrated. Like the die of FIG. 87 and FIG. 88, the two semiconductordie are coupled together through die street 806. The temporary diesupport structure 800 is designed to be removably/releaseably coupled tothe group of die 804 and reduce the warpage of the group of die duringdie packaging operations.

In the implementations illustrated in FIGS. 88 and 89, the permanent diesupport structure 796 and the temporary die support structure 800 eachinclude a material that is applied to the first largest planar surfaceof their respective group of thinned semiconductor die. The materialreduces the warpage of the group of thinned semiconductor die in any ofa wide variety of ways, such as, by non-limiting example, having apredetermined hardness value, having a predetermined stiffness value,having a predetermined Shore value, having a predetermined glasstransition temperature, having a predetermined cure strength, having apredetermined thickness, having a predetermined film stress, curing at aparticular temperature, curing with a particular temperature rampprofile, curing using specific light wavelengths, including one or morefillers, including one or more resins, or any other compound formationprocess parameter, mold compound ingredient, film parameter capable ofaffecting the warpage of the thinned semiconductor die. While a singlelayer of material is illustrated as being used as the permanent diesupport in FIG. 88 or the temporary die support in FIG. 89, in otherimplementations two or more layers of material may be employed to formthe die support which contain either the same or different materialcompositions. These two or more layers may be applied simultaneously orsequentially in various implementations.

A wide variety of forms of materials may be employed in variousimplementations of temporary die supports, including, by non-limitingexample, a coating (which may be applied, by non-limiting example,through painting, sputtering, evaporating, electroplating, electrolessplating, or spraying or any other method of coating), a tape, a film, aprinted structure, a screen printed structure, a stencil printedstructure, an adhesive bonded structure, or any other material formcapable of being removably or releaseably coupled with the surface of asemiconductor die. A wide variety of material types may be employed invarious implementations of temporary die supports, including, bynon-limiting example, polyimides, polybenzoxazoles, polyethylenes,metals, benzocyclobutenes (BCBs), photopolymers, adhesives, and anyother material or combination of materials capable of being removably orreleaseably coupled with a semiconductor die.

In various implementations, the material of the permanent die supportsdisclosed in this document may be mold compounds. In variousimplementations, the mold compound is not a polyimide material or othermaterial generally specifically used to act as a passivating materialfor a semiconductor die surface. The mold compound may include any of awide variety of compounds, including, by non-limiting example,encapsulants, epoxies, resins, polymers, polymer blends, fillers,particles, thermally conductive particles, electrically conductiveparticles, pigments, and any other material capable of assisting informing a stable permanent supporting structure. In some implementationsthe mold compound may be non-electrically conductive (insulative). Inother implementations, the mold compound may be electrically conductive,such as an anisotropic conductive film. In such implementations wherethe mold compound is electrically conductive, the mold compound is not ametal, but rather is formed as a matrix containing electricallyconductive materials, such as, by non-limiting example, metal particles,graphene particles, graphite particles, metal fibers, graphene fibers,carbon fibers, carbon fiber particles, or any other electricallyconductive particle or fiber. In various implementations, the moldcompound may be a material which has a flexural strength of betweenabout 13 N/mm² to 185 N/mm². Flexural strength is the ability of themold compound to resist plastic deformation under load. Plasticdeformation occurs when the mold compound no longer will return to itsoriginal dimensions after experiencing the load. For thoseimplementations of permanent die support structures, flexural strengthvalues of the mold compound to be used may generally be selected so thatthe chosen mold compound has sufficient flexural strength at the maximumexpected operating temperature to avoid plastic deformation.

A wide variety of shapes and structures may be employed as permanent ortemporary die support structures in various implementations that mayemploy any of the material types, material forms, material parameters,or film parameters disclosed in this document to reduce the warpage of agroup of thinned die to any of the desired levels disclosed in thisdocument.

Referring to FIG. 90, an implementation of a permanent die supportstructure 808 that is coupled at the thickness 810 of a group ofsemiconductor die 812. In this implementation, the permanent die supportstructure 808 extends continuously around the thickness/perimeter810/814 of the group of die 812. In this implementation, having thepermanent die support structure 808 around the thickness 810 of the die812 may reduce the warpage of the die 812 to a desired level like anydisclosed in this document.

Referring to FIG. 91, an implementation of a permanent die supportstructure 816 is illustrated that includes two C-shaped or U-shapedportions, a first portion 818 and a second portion 820. The firstportion 818 and second portion 820 are separated by a gap along eachside of the group of semiconductor die 822 which are coupled through diestreet 824. The material of the die support structure 816 in thisimplementation is included in the first portion 818 and second portion820 and may be any material disclosed for use in a permanent die supportstructure disclosed in this document. In other implementations, the twoC-shaped or U-shaped portions may alternatively be coupled across orover the thickness the group of semiconductor die. In otherimplementations, the U- or C-shaped first portion and second portion maybe coupled to the lower largest planar surface of the group ofsemiconductor die rather than the upper largest planar surface 825. Thesame two U- or C-shaped structures may also be employed as a temporarydie support for a group of thinned semiconductor die in the same variouscoupling locations previously described in various implementations.

Referring to FIG. 92, a group of three semiconductor die 826 isillustrated coupled through die streets 828, 830 where at least one ofthe die has a different individual die and the group has anon-rectangular shape to its perimeter 832. An implementation of atemporary die support 834 is coupled to the upper largest planar surface836 of the group of die 826. In this implementation, the temporary diesupport 834 is used to maintain the warpage of the group of die 826below a desired value until the group of die are attached to a substrateand the need for the temporary die support 834 is no longer needed andit is removed.

Referring to FIG. 93, an implementation of a permanent die supportstructure 836 is illustrated. In this implementation, the structure 836is formed of two intersecting lines of material, which are illustratedto be symmetric in at least one axis. In other implementations, however,the shape of the permanent die support structure 58 may be asymmetricabout one or all axes. The locations along the upper or lower planarsurfaces of the group of five semiconductor die 838 at which thestructure 836 is coupled to the die 838 may be determined bycalculations based on, by non-limiting example, individual die size,individual die surface area, individual die shape, localized filmproperties, localized stress gradients, location(s) of semiconductordevices on/within the die, die thickness, die thickness uniformity, andany other parameter affecting the warpage of an individual semiconductordie. Also, in this implementation of a permanent die support structure836, the length, orientation, and or position of each of the projections840, 842, 844, 846 of the structure 836 may be calculated and/ordetermined using any of the previously mentioned parameters affectingthe warpage of a group of die. In FIG. 93, the permanent die support isillustrated with rounded side walls. However, in variousimplementations, different side wall profiles having straight orsubstantially straight side walls may be employed. In variousimplementations, the side wall profile of the permanent die support 836may also be calculated/determined using any of the previously mentionedparameters that affect the warpage of a group of semiconductor diedisclosed in this document. Various implementations of temporary diesupport structures may also utilize any of the aforementioned permanentdie structures.

Various permanent and temporary die support implementations may take theform of a rod/long rectangle with straight or substantially straightside walls. As previously discussed, the profile of the side walls maybe changed to assist in reducing the warpage of the group ofsemiconductor die as can the location of the support and its orientationrelative to the perimeter of the die. In various implementations, therod may not be straight, but may be curved in one or more places toform, by non-limiting example, a C-shape, a U-shape, an S-shape, anN-shape, an M-shape, a W-shape, or any other curved or angled shapeformed from one continuous piece of material (see FIG. 92).

In other implementations of permanent or temporary die supports likethose disclosed in this document, die support structures with a centralportion from which a plurality of ribs project may be utilized. Thenumber, location, and position of the ribs along the central portion maybe determined/calculated using any of the previously discussedparameters that affect the warpage of the group of die. The side wallprofile of any or all of the ribs and/or the central portion may also becalculated in a similar way using the previously discussed parameters.

In various implementations, the temporary or permanent die support neednot be a shape with straight edges/lines, but, like the implementationof a temporary die support 848 illustrated in FIG. 94, may include anelliptical or spherical shape. In this implementation, the overallthree-dimensional shape of the die support 848 is that of a rounded ringas the side wall profile of the material of the ring is rounded. Inother implementations, however, the overall three-dimensional shape ofthe support 848 may be, by non-limiting example, a ring with straight orsubstantially straight sidewalls, cylindrical with straight side walls,conical with angled side walls, frustoconical with straight side wallsand a flat upper surface, or any other three dimensional shape that isformed by projecting an elliptical cross-sectional shape upward from thesurface of a group of die 850.

In various implementations of temporary or permanent die supports,various triangular shapes may be utilized. For those supports that aretriangular, the shape of the triangle may be acute, right, obtuse,equilateral, isosceles, or scalene in various implementations. As in thepreviously discussed, the side wall profile of the triangle and theplacement of the die support along the largest planar surface of a groupof semiconductor die may be determined by any of the previouslymentioned parameters that affect the warpage of the group of die.

Referring to FIG. 95, in various implementation of temporary orpermanent die supports the shape of the die support 852 may be irregularas determined by what is calculated to minimize the warpage of aparticular configuration of multiple die. In the implementationillustrated, the two die 854, 856 are of different sizes, and so the diesupport 852 is designed to contact both but in different locations inorder to minimize the warpage of the largest planar surface 858 of thegroup of die. The sidewall profile of the die support 852, likepreviously discussed, is rounded as determined by what is needed tominimize the warpage of the largest planar surface 858.

In various implementations, the permanent or temporary die support caninclude more than one portion that is not directly attached to any otherportion (see FIG. 91). In various implementations, the specificplacement, sizing, and side wall profile of each of the portions may bedetermined by any of the previously mentioned parameters affectingwarpage of a group of die. While in implementation illustrated in FIG.91, the first portion 818 and second portion 820 are coupled to thelargest planar surface 825, in other implementations the differentportions may be coupled on/at the thickness of the group ofsemiconductor die in a manner similar to the implementation illustratedin FIG. 90. In some implementations, first, second, third, and fourthportions may be coupled around each corner of the group of semiconductordie at the thickness of the group. In other implementations, fourportions may be included but may be coupled at the thickness at themidpoint of each side of the group of semiconductor die. In variousimplementations, portions coupled at the thickness may take a variety ofother shapes, including, by non-limiting example, semicircular,triangular, square, angled, or any other closed shape. In otherimplementations, a single permanent or temporary die support structuremay be coupled along a side of the group of semiconductor die at thethickness; in others, the single permanent or temporary die supportstructure may be coupled on a side and may wrap around one or morecorners formed by the group of semiconductor die.

Referring to FIG. 104, an implementation of a permanent die support 860is illustrated coupled over two die 862. In this implementation, the diesupport 860 takes the form of a frame 868 with curved sections 864, 866extending across the largest planar surface of the two die 862. Theradius of curvature of the curved sections 864, 866 may be determined byany of the various parameters that govern warpage disclosed in thisdocument. While the curved sections 864, 866 are illustrated as beingsymmetrically distributed about the frame 868, in variousimplementations they may be, by non-limiting example, asymmetric aboutone or more axes, have different radii of curvature, extend from anyside of the frame, include one or more sections, extend nearly acrossthe dimension of the frame, or be placed as determined by any of theparameters that control warpage of groups of die disclosed in thisdocument.

In various implementations of permanent die supports like thosedisclosed herein, a permanent die support material may fully encloseboth of the largest planar surfaces and the thickness of a group ofsemiconductor die. Whether the die support fully encloses all six sidesof the group (in the case of a rectangularly shaped group of die)depends on the desired warpage values. In such implementations where thepermanent die support completely covers one or more sides of the groupof die, one or more openings may be provided in/formed in the permanentdie support through the material of the permanent die support to allowelectrical or physical connections with one or more of the group of die.In various other implementations, permanent or temporary die supportmaterial may extend over the thickness and one of the two largest planarsurfaces of the group of semiconductor die. In such implementations,electrical and physical connections made be formed via the exposedlargest planar surface and/or through openings in the material of thedie support. A wide variety of possible configurations may beconstructed to form electrical and physical connections with a group ofsemiconductor die to which a permanent or temporary die support like anydisclosed in this document using the principles disclosed herein. Invarious implementations, the permanent die support material may beconformal, or conform to the shape of the die over which the material iscoupled. In other implementations, the die support material may benon-conformal forming its own shape rather than assuming part of theshape of the die. In various implementations, the permanent die supportmaterial may be applied as a coating to the semiconductor die.

Referring to FIG. 96, in various implementations, a thickness 870 of thedie support material 872 may be thinner than a thickness 874 of thegroup of die 876. In other implementations, as illustrated in FIG. 97, athickness 878 of the die support material 880 may be thicker than athickness 882 of the group of die 884. The particular thickness anduniformity of the thickness of the die support material over thesurfaces of the group of die may be determined using any of the factorsinfluencing the warpage of a group of die disclosed herein.

The various implementations of permanent and temporary die supportstructures disclosed herein may be formed using various methods offorming a die support structure. In a particular method implementation,the method includes permanently or temporarily coupling a material witha two or more semiconductor die. This material may be a mold compound orany other material disclosed in this document used to form a permanentdie support structure. This material may also be any material disclosedin this document used to form a temporary die support structure. Thegroup of semiconductor die may be any type disclosed herein thatincludes two largest planar surfaces with a thickness between thesurfaces and the thickness may be any thickness disclosed in thisdocument. The semiconductor device(s) included on the group ofsemiconductor die may be any disclosed in this document. At the timewhere the material is permanently or temporarily coupled with the groupof semiconductor die, the material may be coupled with any, all, or anycombination of a first largest planar surface, a second largest planarsurface, or the thickness. The method includes reducing a warpage of alargest planar surface of the group of semiconductor die to less than 50microns through the coupling the material. In particular implementationsthe method may include reducing a warpage of a largest planar surface ofthe group of semiconductor die to less than 25 microns.

As disclosed in this document, in various method implementations, themethod includes permanently or temporarily coupling (or temporarily andpermanently coupling in some implementations) two or more portions ofmaterial to the group of semiconductor die to one, all, or anycombination of the first largest planar surface, the second largestplanar surface, or the thickness. In various method implementations, themethod may include permanently or temporarily coupling a second layer ofmaterial over the material originally permanently coupled with thesemiconductor die. Additional layers beyond the second layer may also becoupled over the second layer in various method implementations.

In various method implementations, the point in a group of semiconductordie's processing where the permanent die support structure is coupledmay vary from implementation to implementation. In some methodimplementations, the point at where the permanent die support structureis applied may occur before or after the group of semiconductor die hasbeen physically singulated from among the plurality of semiconductor diebeing formed on a semiconductor substrate. Similarly, in various methodimplementations, the point in processing where a temporary die supportstructure is coupled may vary from implementation to implementation. Insome implementations the temporary die support may be attached prior toattachment of the group of die to a substrate or other attachmentstructure, at which point the temporary die support is removed.

Referring to FIG. 98, an implementation of three groups of semiconductordie 886, 888, 890 are illustrated coupled together in a permanent diesupport 892 which is composed of a mold compound. In thisimplementation, the three groups 886, 888, 890 were molded into thepermanent die support 892 at the same time. Following formation of thepermanent die support 892, the groups 886, 888, 890 are singulated fromeach other using any of a wide variety of process, including, bynon-limiting example, sawing (illustrated), lasering, jet ablating,etching, plasma etching, and any other singulating method. Followingsingulation the groups 886, 888, 890 are then used in subsequent diepackaging operations.

Referring to FIG. 99, four groups of semiconductor die 894, 896, 898,900 are illustrated placed into a jig/mold/guide 902 which is designedto retain the groups in a place. As illustrated, a dispensing process904 is being used to apply a temporary die support structure 906, 908,910, 912 over each of the groups. Following the dispensing, the groups894, 896, 898, 900 are then removed from the jig 902 and used insubsequent die packaging operations. The various implementations, thejig/mold/guide 902 may include various vacuum/air pressureports/openings designed to hold the groups in a desired location and/orretain the groups in a desired warpage value until the temporary diesupport has been applied/formed. Various curing steps may also becarried out to cure/harden the material of the temporary die supports906, 908, 910, 912 while the groups are retained in the jig 902.

Referring to FIG. 100, three groups of semiconductor die 914, 916, 918are illustrated after molding into a permanent die support 920 whilebeing supported by temporary die supports 922, 924, 926. As illustrated,the temporary die supports 922, 924, 926 are now being peeled from thesurface of each of the three groups 922, 924, 926 in preparation for asingulation process (in this case, sawing) like any disclosed in thisdocument.

In various method implementations, the temporary or permanent diesupports may be coupled prior to or after probing of the individualdie/groups of die. Similarly, the temporary or permanent die supportsmay be applied to a plurality of die on a semiconductor substrate priorto or after probing the plurality of die/groups of die.

In various method implementations, no precut or partial grooving betweenthe plurality of die of a semiconductor substrate (or groups of die) maybe carried out. Where the plurality of die (or groups of die) will bethinned, the depth of the die/saw streets/scribe lines may be sufficientto carry out the various methods of forming semiconductor packagesdisclosed herein. For example, and with reference to FIG. 101, where thesemiconductor substrate 928 will be thinned to about 10 microns, theabout 5 micron depth of the die streets 932 into the material of thesubstrate/die resulting from the processing steps that form the groupsof semiconductor die suffices to act as the equivalent of any partialgrooving/precutting. In various implementations, as illustrated in FIG.101, permanent or temporary die support structures 930 may be appliedover the groups of die leaving specific die streets 934 exposed forsubsequent processing.

In particular method implementations, the depth of the exposed diestreets 934 can be increased during the die fabrication process. Inother particular method implementations, the depth of the exposed diestreets may be increased during die preparation/packaging processesfollowing die fabrication. In this way, any separate precut or partialgrooving of the wafer using a saw or other process may be renderedunnecessary. Avoiding separately precutting/partial grooving mayfacilitate the sawing process and/or eliminate risk of sidewall crackingdue to coefficient of thermal expansion (CTE) mismatches. While usingthe depth of the die streets to set sidewall coverage of mold compoundrather than the depth of a precut into the semiconductor substrate mayreduce the partial sidewall coverage for each group of die, the benefitsmay outweigh the additional coverage in various method implementations.

In various method implementations, temporary or permanent die supportstructures may be coupled to the plurality of die while thesemiconductor substrate while it is at full thickness, or, in otherwords, prior to any thinning operations being performed. Additionalthinning operations can then be initiated with the temporary orpermanent die support structures in place. Also, for those processeswhere precut/grooving operations take place prior to thinning, thesesteps can take place after coupling of the temporary or permanent diesupport structures.

In various method implementations, temporary or permanent die supportstructures may be coupled over groups of die after thinning isperformed. In other implementations, the temporary or permanent diesupport structures may be applied over the groups of die after backmetallayer(s) have been applied to the semiconductor substrate. In yet othermethod implementations, the temporary or permanent die supportstructures may be applied over the groups of die after the semiconductorsubstrate has been only partially thinned, such as, by non-limitingexample, through removing backside oxide prior to probing, an initialgrinding step prior to a polishing/lapping step, or any other processwhich partially removes a layer of material or bulk material from theside of the semiconductor substrate opposite the die.

In various method implementations, the temporary or permanent diesupport structures may be applied over the groups of semiconductor dieafter a full backgrinding process is carried out but prior to or after astress relief wet etching process has been carried out. In suchimplementations, the stress relief wet etching may be carried out withor without backmetal. In some implementations, the stress relief wetetching may take place after protecting the front side (die side) of thesemiconductor substrate. The stress relief etching may reduce thebackside damage to the semiconductor substrate that is caused by thebackgrinding process. The use of the stress relief etching may alsofacilitate adhesion of the backmetal applied to the ground surface. Invarious implementations, the application of the temporary or permanentdie support structures may be carried out prior to a backmetal formationprocess. A wide variety of sequences of method steps involving couplingof temporary or permanent die support structures may be carried outusing the principles disclosed in this document for packaging processinvolving wafer scale operations like those disclosed in this documentused for semiconductor substrates.

Referring to FIG. 102, temporary or permanent die support structures 938may be applied to a thinned semiconductor substrate 936 prior tosingulation of the various groups of die. In other implementations,temporary or permanent die support structures may be coupled with thegroups of thinned die after singulation but before picking of the groupsof die while the thinned groups of die are still supported on dicingtape. A wide variety of potential options may exist for the timing ofwhen the temporary or permanent support structures may be applied to thedie during wafer scale packaging operations.

Similarly to the timing of applying temporary or permanent die supportstructures during methods of wafer scale packaging groups of die, thetiming may vary in various implementations of chip scale packaginggroups of die. For example, referring to FIG. 103, a temporary or apermanent die support structure 944, 946 may be applied individually togroups of die 940, 942. Temporary or permanent dies supports may beapplied as the first step following die picking from a singulation tape,or immediately following die singulation prior to picking. In othermethod implementations, a temporary or permanent die support structuremay be applied at or just prior to a later step in the process, such as,by non-limiting example, die attach, die underfilling, flux washing,epoxy cure, prior to a full encapsulating step, after lead frame attach,or any other chip scale packaging process operation. In variousimplementations, temporary die supports may generally be applied priorto die attach, as after die attach there may be no further need for thetemporary die support. A wide variety of sequences of method stepsinvolving coupling a temporary or permanent die support structures maybe employed in various method implementations using the principlesdisclosed in this document.

A wide variety of methods and processes may be employed to remove thetemporary die supports from groups of die at the point in the processwhere the temporary supports are no longer needed. Variousimplementations of a temporary die supports may be peeled off of thesurface of groups of die after or during exposure from a light source.This light source may be, by non-limiting example, a visible lightsource, an infrared light source, an ultraviolet light source, a laserlight source, or any other source of light capable of acting to releaseor assist in releasing the temporary die support. For example, if thetemporary die support was a UV release tape, then the support could bepeeled from the surface of the group of thinned die following exposureto a UV light source for a predetermined period of time after the groupof thinned die had been attached to, by non-limiting example, asubstrate, leadframe, another die, a lead, a redistribution layer, anycombination thereof, or any other die bonding structure.

In various implementations, temporary die supports may be etched from agroup of die using a plasma etching source. While a plasma etchingsource may be used, any other etching process could be employed invarious implementations, including, by non-limiting example, a wetetching process, a spray etching process, a reactive ion etchingprocess, an ion bombardment process, a lasering process, a grindingprocess, or any other process capable of reacting away or ablating thematerial of the temporary die support.

In other implementations, the temporary die support may be removed usingenergy assisting processes. In various implementations, a temporary diesupport may be separated from a group of thinned die in a bath underultrasonic energy produced by ultrasonic energy source. Under theinfluence of the compression waves in the fluid of the bath, thetemporary die support may separate without requiring any pulling force,or the peeling of the temporary die support may be enabled by theultrasonic energy. While the use of a bath 774 is illustrated, invarious implementations a puddle may be used. In still otherimplementations, the ultrasonic energy may be directly or indirectlyapplied to the group of die through a spindle, a chuck, a plate, or aliquid stream. In various implementations, the source of sonic energymay range from about 20 kHz to about 3 GHz. Where the sonic frequenciesutilized by the ultrasonic energy source are above 360 kHz, the energysource may also be referred to as a megasonic energy source. Inparticular implementations, the sonic energy source may generateultrasonic vibrations at a frequency of 40 kHz at a power of 80 W. Invarious implementations, the sonic energy source may apply a frequencyof between about 30 kHz to about 50 kHz or about 35 kHz to about 45 kHz.However, in various implementations, frequencies higher than 50 kHz maybe employed, including megasonic frequencies. A wide variety of powerlevels may also be employed in various implementations.

In various semiconductor package and method implementations disclosed inthis document, any of the pads or electrical connectors disclosed inthis document may be formed, by any or any combination of the following:evaporation, sputtering, soldering together, screen printing, solderscreen printing, silver sintering one or more layers of materials. Anyof the foregoing may also be used in combination with electroplating orelectroless plating methods of forming pads and/or electricalconnectors.

Referring to FIG. 105, a cross sectional side view of a semiconductorsubstrate (wafer) 948 is illustrated. FIGS. 105-111 illustrate thesemiconductor substrate 948 after various steps in an implementation ofa method of forming a semiconductor package that contains a thinnedsemiconductor die. The thinned semiconductor die may have any thicknessdisclosed herein. In implementations of semiconductor packages, thethinned semiconductor die may have any warpage value disclosed herein asthe various components of the package may form a permanent and/ortemporary die support structure that reduces the warpage of the die. Asillustrated, the semiconductor substrate 948 includes a first side 950and a second side 952. The semiconductor substrate in variousimplementations may be a wafer (referred to interchangeably herein) andmay include any semiconductor substrate material type disclosed in thisdocument. The first side 950 of the wafer 948 includes or is coupled toa plurality of electrical contacts 954. The electrical contacts 954 maybe metallic or made of another material that is electrically conductiveand may be deposited and formed using various methods of formingpatterned metallic materials.

In various implementations, the method includes forming a plurality ofnotches 956 in/into the first side 950 of the wafer 948. In variousimplementations, the plurality of notches may intersect one another in asubstantially perpendicular direction across the first side 950 of thewafer 948. However, in other implementations, where the perimeter of thesemiconductor die included on the wafer are not rectangular, theplurality of notches may or may not intersect with one another acrossthe surface of the first side of the wafer 950 and may, in someimplementations, form a closed shape around the perimeter of eachsemiconductor die. In various implementations, the plurality of notches956 formed may extend about 25 or more microns deep into the wafer. Inother implementations, the notches 956 only extend between about 10 andabout 25 microns deep in the wafer 948. In still other implementations,the notches 956 extend less than about 10 microns deep in the wafer 948.The plurality of notches 956 may be formed using, by non-limitingexample, a saw, a laser, a waterjet, plasma etching, or chemicaletching. In various implementations, a chemical etching process marketedunder the tradename BOSCH® (the “Bosch process”) by Robert Bosch GmbH ofStuttgart, Germany, may be used to form the notches 956 in the firstside 950 of the wafer 948.

In various implementations, the notches 956 formed have twosubstantially parallel sidewalls that extend substantially straight intothe material of first side 950 of the wafer 948. In otherimplementations, a plurality of stepwise or stepped notches are formedin the first side 950 of the wafer 948. Each stepped notch may be formedby forming a first notch in the wafer having a first width, and thenforming a second notch with a second width within each first notch wherethe first width is wider than the second width.

In some implementations, the notches may not be separately formed fromthe semiconductor substrate manufacturing process used to form theplurality of semiconductor die that are included in/on the semiconductorsubstrate. In such implementations the notches may be the die streetsthemselves. In various die street implementations, the depth of the diestreets may extend about 1 to about 10 microns into the material of thesemiconductor substrate. Where the semiconductor substrate is thinned toless than 25 microns thick, the die streets may provide sufficient depthinto the semiconductor substrate to enable to the various semiconductordie to be singulated using die streets themselves. In suchimplementations, the subsequent processing disclosed herein may becarried out with the die streets functioning as the notches.

Referring to FIG. 106, the substrate 948 is illustrated followingapplication of a permanent coating material 958 into the plurality ofnotches 956. The permanent coating material 958 may be any of a widevariety of organic materials including, by non-limiting example,polyimide, benzocyclobutene, a liquid encapsulant, a mold compound, aphotodefinable material, an etchable material, or any other organicmaterial. The permanent coating material 958 may be applied using, bynon-limiting example, a photolithography process, a screen printingprocess, a dispensing process, a printing process, a screen printingprocess, a spraying process, an etching process, any combinationthereof, or any other process of applying a liquid or deformablematerial into the plurality of notches. As illustrated in FIG. 106, thepermanent coating material 958 extends up to the surface of the firstside 950 of the wafer 948. However, in other implementations, thepermanent coating material 958 may extend only partially up the sidewalls of the plurality of notches 956. In other implementations, thepermanent coating material may extend above the first side 950 of thewafer provided it extends no higher than the upper surface of theelectrical contacts/connectors 954.

Following application/formation of the permanent coating material 958into the plurality of notches 956, referring to FIG. 107, the wafer 948is illustrated following coating the first side 950 of the wafer 948 andthe interiors of the plurality of notches 956 with an organic compound960. The organic compound 960 may also cover the electrical contacts 954in various method implementations. The organic compound 960 may beapplied using, by non-limiting example, a liquid dispensing technique, atransfer molding technique, a printing technique, an injection moldingtechnique, a compression molding technique, or any other method ofapplying an organic compound.

The organic compound may be, by non-limiting example, an epoxy moldingcompound, an acrylic molding compound, a resin, a mold compound, anyorganic material disclosed herein, or any other organic compound capableof hardening and providing physical support and/or humidity protectionto a semiconductor device. In various implementations, the organiccompound may be a mold compound and may be cured under a temperaturebetween about 100-200 degrees Celsius and while a pressure ofsubstantially 5 psi is applied to the second side 952 of the wafer 948.In other implementations, the organic material may be cured withdifferent temperatures and different pressures or may not be cured usinga temperature and/or pressure process. In implementations where an epoxymolding compound is used as the organic material, after the organicmaterial 960 is applied, it may be heat treated to enhance the epoxycross linking.

In various implementations, the method includes thinning the second side952 of the wafer 948 to a desired thickness. Referring to FIG. 108, invarious implementations the second side 952 of the wafer 948 may bethinned away to an extent that the plurality of notches 956 filled withpermanent coating material 958 extend completely through the wafer 948,thereby singulating the various semiconductor die. In variousimplementations, more material of the wafer can be ground away, thusdecreasing the depth of the plurality of notches 956 themselves. In thisway the semiconductor devices in the wafer are separated from eachother, but still held together through the organic material 960 and thepermanent coating material 958. Because the organic material 960 nowsupports the semiconductor devices, the semiconductor substrate can bethinned to any thickness of a semiconductor die disclosed in thisdocument. In various implementations, the second side 952 of the wafer948 may be thinned using, by non-limiting example, a mechanicalpolishing technique, a chemical etching technique, a lapping technique,a combination of a mechanical polishing and chemical etching technique,any combination thereof, or any other semiconductor thinning process.

In various implementations, referring to FIG. 109, the method mayinclude applying/forming a second organic material or a backmetal 962 tothe second side of the wafer 948. Prior to this step, in various methodimplementations, the method may include performing a stress relief etchlike any disclosed in this document to relieve stress and/or repairdamage in the thinned second side 952 of the wafer 948. In those methodimplementations where a second organic material 962 is applied thesecond organic material may be any organic material disclosed in thisdocument and may be applied using any method for applying/forming anorganic material disclosed in this document. In those methodimplementations where a backmetal/back metal 962 is formed on the secondside 956 of the wafer 948, the back metal may include a single metallayer or multiple metal layers. In various implementations, the backmetal may include, by non-limiting example, gold, titanium, nickel,silver, copper, or any combination and/or alloy thereof. Because thewafer 948 is thinned and the back metal 962 is applied to the thinnedwafer 948 while the entirety of the first organic material 960 iscoupled to the first side 950 of the wafer 948, it may be possible toreduce or eliminate warpage of the wafer 948. In such implementations,the first organic material 960 becomes a permanent die support structureor a temporary die support structure (or a combination of both dependingon the structure of the material 960). In other implementations, it isthe second organic material or backmetal 962 which acts to reducewarpage of the wafer 948. In such implementations, the second organicmaterial or the back metal 962 become a permanent die support structureor a temporary dies support structure (or a combination of both). Insome implementations, the combination of the first organic material 960and the second organic material 962 form a permanent die supportstructure or a combination of a permanent and a temporary die supportstructure.

The structure of the permanent die support structure or the temporarydie support structure may be any such structure disclosed in thisdocument. The use of a permanent or temporary die support structureformed of the first organic material 960 may be particularly helpful toprevent curling and warpage of the semiconductor die now coated withback metal.

Referring to FIG. 110, the wafer 948 is illustrated following exposingthe plurality of electrical contacts 954 covered by the first organicmaterial 960 by thinning a first side 964 of the first organic material960. The first side 964 of the first organic material 960 may be thinnedusing, by non-limiting example, a grinding technique, a mechanicalpolishing technique, a chemical etching technique, a combination of amechanical polishing and chemical etching technique, or any otherthinning technique effective for an organic material.

Referring to FIG. 111, the method implementations include singulatingthe wafer 948 into a plurality of semiconductor packages 966. The wafermay be singulated by cutting or etching through the permanent coatingmaterial 958 where the plurality of notches 956 were originally located.The package materials may be singulated by using, by non-limitingexample, a saw, a laser, a water jet cutting process, plasma etching,chemical etching, or any other method of singulating the materials ofthe permanent coating material and/or the organic material and/or thebackmetal. The method implementation may include using thinner cuts oretches than were used to form the plurality of notches 956. In thismanner, the molding compound 960 covers the front side 950 of thesemiconductor die 948 and the permanent coating material 958 covers thesurface of at least part of the thickness of the sides of the die 948.The ability of the permanent coating material 958 to coat at least partof the thickness of the sides of the die may be helpful where using someforms of molding compound may tend to crack from the thickness. The useof the permanent coating material 958 may improve the creep propertiesof the semiconductor packages formed.

Referring now to FIG. 112, a cross sectional view of a semiconductorsubstrate 968 with a plurality of notches 970 formed therein isillustrated. The substrate 970 illustrated in FIG. 112 may be the sameor similar to the package illustrated in FIG. 111 including electricalconnectors 972. The plurality of notches 970 may be formed using any ofthe methods disclosed in this document and may be stepped notches invarious implementations. The plurality of notches 970 may also intersector otherwise extend around the perimeter of the semiconductor dieincluded in the substrate/wafer 968 as previously described with theimplementation illustrated in FIG. 111.

FIGS. 112-119 illustrate the wafer 970 after various steps of animplementation of a method of forming a semiconductor package have beenimplemented. The method implementation illustrated in FIGS. 112-119 issimilar to the process illustrated in FIGS. 105-111, with the exceptionthat the second side 974 of the wafer 968 is not thinned down to/intothe plurality of notches 970 but toward the plurality of notches 970.Because of this, a portion 976 of the wafer 968 exists between theplurality of notches 970 and the back metal/second organic layer 978. Invarious implementations, about 90-95% of the thickness of the wafer 968is removed through thinning. In other implementations, more or less thanthis percentage of the thickness may be removed through thinning.Thinning may be carried out using any thinning process disclosed herein.As indicated in FIG. 113, a permanent coating material 980 is appliedinto the plurality of notches 970. The permanent coating material 980may be any disclosed in this document. FIG. 116 illustrates how either asecond organic material or a backmetal 978 is applied following thethinning operation. As previously described, a stress relief etch likeany disclosed herein may be applied to the second side 980 of the wafer968. The other process steps in the method implementation (applicationof organic compound, thinning of the organic compound, and singulation,etc.) are carried out similarly to the method implementation illustratedin FIG. 105-111. In addition, the method steps involving formation of apermanent die support structure, temporary die support structure or anycombination of permanent and temporary die support structures using thefirst organic material 984 and the second organic material 978previously described may be employed as well in various methodimplementations.

Referring to the process flows illustrated in FIGS. 21 and 23, the stepof applying a permanent coating material may be included following thestep of forming the plurality of notches in both process flows.Accordingly, these method implementations may also include the step ofapplying the permanent coating. As a result, the package implementationsillustrated in FIGS. 22 and 24 will include permanent coating materialin the notched/grooved regions in the semiconductor die instead of themold compound/first organic material described herein. Such method andpackage implementations may also include forming a permanent die supportstructure, a temporary die support structure, or both a permanent diesupport structure and a temporary die support structure as previouslydisclosed.

The resulting package 980 is illustrated in FIG. 120. As illustrated,because the material of the semiconductor substrate 968 is not thinnedto the depth of the plurality of notches 970, the permanent coatingmaterial 980 only extends partially along the side 982 of the packagethat corresponds with the thickness of the substrate 968. In thisimplementation, where the material on the second side 986 of the packageis organic material, the material may function as a permanent diesupport 988 for the semiconductor die 968. In other implementations,where the material on the second side 986 of the package is backmetal,then the first organic material 984 may act as a permanent die support990 for the semiconductor die 968. In various implementations, thevarious die support structures may include two or more layers and maytake the form of any of the permanent or temporary die supportstructures included herein.

Referring to FIG. 121, another implementation of a semiconductor package992 is illustrated. In this implementation, like the previouslyillustrated implementations, permanent coating material 994 covers theentire side of the semiconductor die 996 that crosses the thickness ofthe die. This package implementation is formed using a methodimplementation similar to that illustrated in FIGS. 105-111 except thatthe electrical connectors 998 are formed through forming multiple layersof electrically conductive material 1000, 1002, 1004. These electricallyconductive materials may be any disclosed in this document including, bynon-limiting example, solders, solder pastes, or solder resists.Backmetal 1006 is also formed on the semiconductor die 996. In thisimplementation, the mold compound 1008 may act as a permanent diesupport depending on the thickness of the semiconductor die, thebackmetal 1006, and the desired value of warpage of the die 996.

In places where the description above refers to particularimplementations of semiconductor packages and implementing components,sub-components, methods and sub-methods, it should be readily apparentthat a number of modifications may be made without departing from thespirit thereof and that these implementations, implementing components,sub-components, methods and sub-methods may be applied to othersemiconductor packages and related methods.

What is claimed is:
 1. A method of forming a semiconductor package, themethod comprising: forming a plurality of notches into the first side ofa semiconductor substrate; applying a permanent coating material intothe plurality of notches; forming a first organic material over thefirst side of the semiconductor substrate and the plurality of notches;thinning a second side of the semiconductor substrate opposite the firstside one of to or into the plurality of notches; and singulating thesemiconductor substrate through the permanent coating material into aplurality of semiconductor packages.
 2. The method of claim 1, furthercomprising applying one of a second organic material or a backmetal overthe second side of the semiconductor substrate.
 3. The method of claim1, wherein a perimeter of each of a plurality of semiconductor diecomprised in the semiconductor substrate each comprises a closed shape.4. The method of claim 1, wherein forming a first organic material overthe first side of the semiconductor substrate further comprises forminga permanent die support structure, a temporary die support structure, orany combination thereof comprising a perimeter comprising a closedshape.
 5. The method of claim 4, further comprising forming one of asecond permanent die support structure or a temporary die supportstructure coupled to the second side of the semiconductor substrate. 6.The method of claim 4, wherein the one of the permanent die supportstructure, the temporary die support structure, or any combinationthereof comprises two or more layers.
 7. A method of forming asemiconductor package, the method comprising: forming a plurality ofnotches into a first side of a semiconductor substrate; applying apermanent coating material into the plurality of notches; forming afirst organic material over the first side of the semiconductorsubstrate and the plurality of notches; thinning a second side of thesemiconductor substrate opposite the first side toward the plurality ofnotches; and singulating the semiconductor substrate through thepermanent coating material into a plurality of semiconductor packages.8. The method of claim 7 further comprising applying one of a secondorganic material or a backmetal over the second side of thesemiconductor substrate.
 9. The method of claim 7, a perimeter of eachof a plurality of semiconductor die comprised in the semiconductorsubstrate each comprises a closed shape.
 10. The method of claim 7,wherein forming a first organic material over the first side of thesemiconductor substrate further comprises forming a permanent diesupport structure, a temporary die support structure, or any combinationthereof comprising a perimeter comprising a closed shape.
 11. The methodof claim 10, further comprising forming one of a second permanent diesupport structure or a temporary die support structure coupled to thesecond side of the semiconductor substrate.
 12. The method of claim 10,wherein the one of the permanent die support structure, the temporarydie support structure, or any combination thereof comprises two or morelayers.
 13. The method of claim 7, further comprising forming a secondplurality of notches into the second side of the semiconductorsubstrate.
 14. A method of forming a semiconductor package, the methodcomprising: forming a plurality of notches into the first side of asemiconductor substrate; applying a permanent coating material into theplurality of notches; forming a first organic material over the firstside of the semiconductor substrate and the plurality of notches; andsingulating the semiconductor substrate through the permanent coatingmaterial into a plurality of semiconductor packages.
 15. The method ofclaim 14, further comprising applying one of a second organic materialor a backmetal over the second side of the semiconductor substrate. 16.The method of claim 14, wherein a perimeter of each of a plurality ofsemiconductor die comprised in the semiconductor substrate eachcomprises a closed shape.
 17. The method of claim 14, wherein forming afirst organic material over the first side of the semiconductorsubstrate further comprises forming a permanent die support structure, atemporary die support structure, or any combination thereof comprising aperimeter comprising a closed shape.
 18. The method of claim 17, furthercomprising forming one of a second permanent die support structure or atemporary die support structure coupled to the second side of thesemiconductor substrate.
 19. The method of claim 17, wherein the one ofthe permanent die support structure, the temporary die supportstructure, or any combination thereof comprises two or more layers. 20.The method of claim 14, wherein the first organic material is directlycoupled to the first side of the semiconductor substrate.